How Poison Ivy Works

Josh: Josh Clark

Chuck: Charles W. "Chuck" Bryant

Vo: Voiceover Speaker

Chuck: This episode is brought to you by Squarespace. Squarespace recently launched the latest version of their platform, Squarespace 7, which has a completely redesigned interface, integrations with Getty Images and Google Apps, new templates, and an incredible feature called Cover Pages. Try the new Squarespace at, and enter the offer code STUFF at checkout to get 10% off. Squarespace: "Start here. Go anywhere."


Josh: Hey, everybody. It's Josh and Chuck from Stuff You Should Know, like you didn't know. [LAUGHS] And we wanted to tell you that we are going to be on the West Coast at the end of March, beginning of April, for a live podcast tour.

Chuck: That is right. We are going to be in L.A. on March 30th.

Josh: Yep. We'll be in Los Angeles March 30th.

Chuck: At the Palace Theatre downtown. That following night, we will be jetting up to San Francisco at the Palace of Fine Arts, which I'm stoked about.

Josh: It's lots of palaces.

Chuck: Lots of palaces. The following night, we are going to be-

Josh: April 1st.

Chuck: -in Portland.

Josh: No joke.

Chuck: At the Aladdin Theater. And then we're going to wind up in Seattle on April.

Josh: 2nd.

Chuck: At the Neptune Theatre.

Josh: Right.

Chuck: And you can get all the information-tickets are already on sale. They're going fast, so you need to get on it.

Josh: Yeah.

Chuck: But just go to, and if you were impressed with how clean and lovely that website is, it's because it was built by our friends at Squarespace, who are sponsoring the tour.

Josh: That's right. Our friends at Squarespace are hooking us up, hooking you up. Just come on out and you'll see what we're talking about.

Chuck: Yeah, and by the way, the L.A. theater has assigned seating, and so you want to get your tickets fast for L.A. so you don't end up, you know, in a bad seat. Let's just go ahead and say it. [LAUGHS]

Josh: Hey, there are no bad seats when we're onstage, Chuck.

Chuck: That's true.

Josh: So go to, and get your tickets and we'll see you there.


Vo: Welcome to Stuff You Should Know, from


Josh: Hey, and welcome to the podcast. I'm Josh Clark. This is Charles W. "Chuck" Bryant. There's Jeri. And all this is stuff you should know.

Chuck: You looked like you were about to describe the room, and then you just went, "Eh."

Josh: It's too depressing in here.

Chuck: Yeah, and you know we should-we might as well announce that we're moving. I don't think we've announced that yet, have we?

Josh: No, we haven't.

Chuck: No, we are finally moving-you know, we've been in this building since-you and I and Jeri have been here-

Josh: Yeah.

Chuck: Actually since How Stuff Works has been around, right?

Josh: I think it started in North Carolina.

Chuck: Oh, well, no. I mean-

Josh: In Marshall Brain's kitchen.

Chuck: No, no, I mean the Atlanta version.

Josh: I genuinely don't know, but probably.

Chuck: Yeah, so we've been in this building in Buckhead, Atlanta, that's not super exciting, and our first office was kind of cool; this one is decidedly not cool.

Josh: We call this one the call center, for good reason.

Chuck: Yeah, it's really-it's just not a creative space. And so when we were sold by Discovery Channel this summer, our new parents, Blucora, said, "Let's move you into a cool, creative, awesome new space."

Josh: Yep.

Chuck: And we are all super excited, except for you, probably, with the commute.

Josh: Yeah, but, I mean-

Chuck: You're still excited.

Josh: -it's a good space. It's pretty cool. I mean, there's going to be an izakaya downstairs.

Chuck: Yeah.

Josh: You know?

Chuck: Yeah.

Josh: I think it's the same people that developed the Chelsea Market.

Chuck: Yeah, in New York City.

Josh: Yeah, so they're doing something here, too, and we're moving into it.

Chuck: Yeah, it's called Ponce City Market, and it is the old Sears building from the early 1900s, which I used to go to as a kid when it was Sears.

Josh: In the 1900s.

Chuck: [LAUGHS] Very funny. Well, it was the 1900s-1980s.

Josh: Oh, wow, that was-

Chuck: And '70s.

Josh: Not bad, Chuck.

Chuck: You were thinking 1920s, though.

Josh: Yeah.

Chuck: I know where you were going. So we're trying to have a bigger presence in Atlanta, and be a little more visible.

Josh: And the world.

Chuck: And the world. And so we're going to have a cool, new office space, and it's just awesome, so thanks to our boss Jason, and Jeri, for working so hard on all this, and Michael and Izzy, and everyone's done a great job, and we're moving in, like-these are the last six shows or so we're recording here.

Josh: Yeah.

Chuck: Ish-until we move into our new place.

Josh: Yeah.

Chuck: So I just wanted to say that. We're super excited.

Josh: That was nice, Chuck.

Chuck: Yeah.

Josh: Hats off to you, too.

Chuck: Yeah, killed a few minutes.

Josh: Nice going.

Chuck: So that has nothing to do with poison ivy, at all.

Josh: No, and as a matter of fact, I'll bet there's not much poison ivy around Ponce City Market.

Chuck: No, I hope not.

Josh: It seems like the kind of place where they would keep the poison ivy under control.

Chuck: Yeah, and I imagine this, also, by the way, will be a show where there will be many people scratching themselves.

Josh: I did, while I was researching. Matter of fact, I just scratched my ear while you said that.

Chuck: Yeah, but that had nothing to do with poison ivy.

Josh: I have a poison ivy story for you.

Chuck: All right, let's hear it.

Josh: So actually, when I lived in the Highlands, let's see-not too far from Ponce City Market.

Chuck: Yeah.

Josh: Umi and I had this house we were renting.

Chuck: I remember that house.

Josh: And it had a pretty substantial poison ivy vine growing up this big oak tree.

Chuck: Where?

Josh: In the front yard.

Chuck: Oh, front yard.

Josh: Yeah, you probably wouldn't have seen it.

Chuck: Nah, I came around the back.

Josh: Right. I, for some reason, had a suspicion that I was immune to poison ivy.

Chuck: Dude, I remember this.

Josh: I don't know why I thought that, but I did. Even still, I took, you know, some precautions; I wore, like, gloves and a long-sleeved shirt and jeans and boots and everything, like you're supposed to. And then I went out and decided to take this thing out.

Chuck: Yeah, that's when you were in your homesteading days.

Josh: Right. So first thing's first, you have to chop the vine, right, because it grows alongside the tree; it latches onto it to grow up.

Chuck: Yeah, it can.

Josh: So when it gets its meat hooks onto the tree-I think that's technical term for it-it's kind of tough to pull away. So you want to chop it off first, and then you pull it away from the tree, and this thing was growing way up this oak tree. It was a substantial poison ivy vine. So when I pulled it down, not only did a lot of the poison ivy detritus fall down onto me, the whole vine-like a 20-foot vine just fell down on top of me. And I'm looking up as this stuff is falling down; it's going into my face, it's getting under my shirt, it's going into my mouth, my eyes. It's everywhere. And I'm thinking, "Man, I'm really glad I'm immune to poison ivy." Still, I don't remember why I thought this.

Chuck: I'm picturing you standing there with your mouth wide open.

Josh: Pretty much, like, "Wow, that's a lot of poison ivy that just came down." And so I'm standing there, I'm starting to clean it up, and as I-no rash is coming around. I'm like, "Awesome. I am immune to poison ivy. I was right." Because it's been like two minutes and no response.

Chuck: Sure.

Josh: Well, fast-forward to an hour or two later.

Chuck: Is that all?

Josh: It was pretty quick. I was like, "Oh no." I told Umi, too, I was like, "I'm immune." And she was like, "You need to get out of those clothes and take a shower," but it was too late, and I guess you remember.

Chuck: I do.

Josh: It was really bad for a couple of weeks.

Chuck: Yeah, I have always thought I am immune, and I may be, because I've still never gotten poison ivy, at all.

Josh: That is really surprising.

Chuck: Yeah, and I've been in contact with it plenty as an outdoors enthusiast, and a camper and hiker. But I remember-I was telling Jeri, in between, my father used to get it like crazy, like one of the memories I have as a child is my dad seemed like he constantly had poison ivy. And that pink-what is it, calamine lotion?

Josh: Yes.

Chuck: Just constantly slathered on his body.

Josh: That poor guy.

Chuck: And a lot of myths being bandied about, like I would catch it from him, or don't scratch because you'll spread it. Neither one of those things are true.

Josh: No. Judd Apatow's wife lied in Big Daddy.

Chuck: Did she say that in Big Daddy?

Josh: Yeah, she was like-the little kid was scratching, and she was like, "Don't let him scratch. Here, put this frozen broccoli on it. It'll spread the rash if you scratch it."

Chuck: Not true.

Josh: Which is a lie.

Chuck: So knock wood, I still have not gotten poison ivy, and that was one of our best intros ever.

Josh: It's a good one. I'm itchy now.

Chuck: Yeah.

Josh: So let's talk about poison ivy, Chuck.

Chuck: I always like a good story where one of us is a bonehead.

Josh: Man, I can't believe-and I think it was just from having been outside and not getting a rash from poison ivy, but I guess I just hadn't come into contact with it.

Chuck: Well, no, or we've learned that you could have been immune for a while and developed after repeated exposure.

Josh: Yeah.

Chuck: That can happen, too.

Josh: But usually it goes the opposite way.

Chuck: Oh, the more exposure, the less it happens.

Josh: Yeah, which is why a lot of adults basically age out of an allergy to poison ivy, if they come in contact with it enough times.

Chuck: I'll have to ask my dad, actually, next time I see him.

Josh: So apparently, back in the day, poison ivy was used as an ornamental shrub or vine, because it comes in both varieties. And then they were like, something that causes this much of a reaction in humans has to have some sort of medicinal benefits.

Chuck: Right.

Josh: And actually there was at least one guy who really researched poison ivy as a medicine. And supposedly he cured skin ailments.

Chuck: Really?

Josh: He made some sort of tonic that he drank-

Chuck: Whoa.

Josh: -and said it cured a stomach ailment, although it made him sweat and urinate more than usual. And this guy was a real urinator, too, so that's something.

Chuck: Oh, he was.

Josh: But he apparently was one of the only people who really looked into it, and other scientists were like, "We're just leaving that thing alone."

Chuck: I think the Native Americans did, though, right?

Josh: I did not see that.

Chuck: Okay, I think I saw that somewhere.

Josh: They used it for medicine?

Chuck: Yeah, which shouldn't be surprising, because they had a lot of homespun sciences.

Josh: They had it figured out.

Chuck: Sure.

Josh: But it wasn't until, I think, the-well, the early 20th century that a Japanese researcher by the name of Majima isolated what it was in poison ivy that makes us allergic.

Chuck: Which is why it has a Japanese name, correct?

Josh: Yes, that's exactly right.

Chuck: Which is urushiol: U-R-U-S-H-I-O-L.

Josh: Yeah, after the Japanese urushi, which means lacquer.

Chuck: Yeah, and basically it is the chemical that is in the sap that is what causes the rash. And apparently the rash is actually called poison ivy, as well.

Josh: Oh, really?

Chuck: Well, that's what it says here. It says, "Poison ivy is the red, itchy rash caused by the plant that bears its name."

Josh: Oh, yeah.

Chuck: So I always just called it-well, people say, "You got poison ivy?"

Josh: Yeah, that's right. I never thought of it like that.

Chuck: I didn't either, actually.

Josh: That's exactly right.

Chuck: So-

Josh: What a breakthrough.

Chuck: [LAUGHS] Yeah, that's amazing. And the way you get poison ivy is by coming into direct contact with this urushiol. It's in the plant, it's in the leaves, it's in the roots, it's in the stems, and you can get it not only-well, you have to come into contact with that, but it doesn't mean from the plant. It can be on a garden rake handle, or a football that you throw in the woods, or your animal's fur.

Josh: That's right.

Chuck: But it still has to be that actual chemical compound.

Josh: And it's got staying power, too. Supposedly urushiol can stay potent for years.

Chuck: Yeah, I saw that a rake from last summer, if you pick it up the next year, you can still get it.

Josh: Yep.

Chuck: That's insane.

Josh: So Chuckers, if you are immune to poison ivy, as you claim, you fall into the lucky 15% of people.

Chuck: Yeah.

Josh: Estimated who are immune to poison ivy. But for the rest of us, the 85%, we are allergic to urushiol.

Chuck: Yeah, and it doesn't take much. They say here, one-billionth of a gram is all it takes sometimes, and this is not just poison ivy. We should point out there is also poison sumac, and poison oak, and Western-or Eastern and Western poison oak, which are all part of the same family that I'm not going to try to pronounce.

Josh: Let me give it a try. Anacardiaceae.

Chuck: [LAUGHS]

Josh: Man, I said it out loud while I was studying and it didn't take. Anacardiaceae. Anacardiaceae. Anacardiaceae.

Chuck: Okay, that sounds about right. When you get that many vowels, it's very difficult.

Josh: Yeah, the A-C-E-A-E at the end really kind of messes you up, but aceae. Yeah, so Anacardiaceae.

Chuck: Yeah, I think that's right.

Josh: I did it.

Chuck: One day, we're going to practice these things 12 times before we record, instead of on the air.

Josh: Makes for a riveting podcast.

Chuck: So like I said, it's in the stems, the leaves, the roots-

Josh: The whole shebang.

Chuck: If you want to avoid the rash, you have to avoid the plant, and just because the old saying "leaves three, leave it be" is true in a lot of cases-but not always.

Josh: Homer Simpson says, "Leaves of four, eat some more."

Chuck: [LAUGHS] I think I remember that. That's so funny.

Josh: And you said that it's found in the roots, the stems, the leaves, the whole shebang.

Chuck: Yep, the whole shebang.

Josh: But even after the plant dies, urushiol can stick around. That's how tough this stuff is.

Chuck: Sure, like you killed that vine in your front yard, and what did you do? Did you leave it there, or did you eventually get around to-?

Josh: Oh, I cut it and pulled it right down. It was as potent as the day is long when I cut it.

Chuck: No, but what did you do after it was laying there on the ground?

Josh: I just cleaned it up. I was immune, remember?

Chuck: Oh, so you finished it up and put it in a garden bag or something?

Josh: Yeah, I was all-I might as well have just rolled in it naked.

Chuck: Yeah, you probably thought, though, you were like, "Yeah, I showed you."

Josh: Yeah, I think I probably was cursing as I was pulling it because it was hanging onto the tree so much.

Chuck: Oh, yeah, man. That stuff is like cement.

Josh: Meat hooks.

Chuck: But the point being, even after you had killed it and chopped it up into tiny pieces, it still has that active ingredient.

Josh: And like you said, it doesn't take much, like a billionth of a gram.

Chuck: That's right.

Josh: That's not very much of this stuff. That's like a drop.

Chuck: [LAUGHS] It's less than a drop.

Josh: Yeah.

Chuck: So we said the leaves three is a good rule to go by. The center leaf is usually larger, but not always. Here's some other ways to identify it, though: it's generally in low-in a cluster, like a low, weed-like-or a vine, like you said, that can climb. So it's either along the ground, or it's climbing.

Josh: This isn't helping differentiate.

Chuck: No, it really isn't. By riverbanks, in the woods, moist areas; if you go hiking a lot or camping, you're going to see it everywhere. And the leaves are smooth and have a little teeth, sometimes.

Josh: Serrated.

Chuck: Yeah, like a serrated edge. That's a good way to put it.

Josh: Their color also changes, which makes it difficult-

Chuck: I didn't know that.

Josh: I don't really remember that, either.

Chuck: I had no idea.

Josh: I thought it just turned brown. I thought they went from green to brown, when it went dormant-when the actual plant goes dormant.

Chuck: Apparently it's a seasonal thing, like reddish, then green, then yellow.

Josh: Yeah, which is another reason why they were sold as ornamental vines for a while.

Chuck: That makes sense.

Josh: But yeah, people were like, "No, this is just foolishness."

Chuck: And white berries, apparently and-well, let's take a message break, and then we'll talk a little bit about the oaks and sumacs.

Josh: Oh, boy.

Chuck: Right after this.


Josh: Chuck?

Chuck: Yeah?

Josh: You know the internet used to be okay, kind of cool, sure-somewhat, I guess, all right, until Squarespace came along.

Chuck: Yeah, because you know, back in the day, if you wanted your own website, man, you had to hire some nerd who knew how to write code, and now Squarespace makes it, like, so anyone can do it. It's just drag-and-drop, and if you've got a finger to click with and two eyeballs, you can make your own website.

Josh: That's exactly right, and now they're launched Squarespace 7. They've redesigned the Squarespace interface to integrate it with Google Apps, they've partnered with Getty Images, there's new templates and Cover Pages. It's beautiful.

Chuck: Yeah, and they have terrific and renowned support, 24-7. You can chat live with people, but you're probably not even going to need to because it's so easy to use and design your own site.

Josh: Exactly. And for only $8 a month, you get a free domain if you buy Squarespace for the year. There's responsive design so your website scales to look great on any device, which is hugely important. And if you want to sell something, they have commerce support available.

Chuck: Right now, we have a special deal for you, thanks to Squarespace. When you go to checkout, just enter the offer code STUFF, and you're going to get 10% off the already cheap prices.

Josh: That's right, and we want to say thanks to our pals at Squarespace for sponsoring our tour.

Chuck: Yeah, we're on the West Coast tour: Los Angeles, San Francisco, Portland, Seattle. And Squarespace came aboard because they're just awesome that way, and we couldn't have had better friends to come aboard and help us out.

Josh: So if you want to show your support for Stuff You Should Know, go to, and use the offer code STUFF to get 10% of your first purchase. Squarespace: "Start here. Go anywhere."


Chuck: All right, oaks and sumacs, my friend. They are a little different in appearance.

Josh: Yes, so poison oak is called that because it grows into a shrub.

Chuck: Oh, I've never thought about that.

Josh: So you walk along and you're like, "Oh, look at this cute little oak tree. You're going to be so big one day." [LAUGHS] And you put your face all over it or whatever.

Chuck: Yeah, yeah.

Josh: You got poison oak on your face, you dummy. Don't ever get too close to an oak sapling because it could kill you and your whole family if they wanted to.

Chuck: That's right, and they can be from a foot to six feet tall, and on the West Coast and in the South-although I don't think we said that you're going to find poison ivy everywhere, but it said Southwest, but I looked at a map, and it looked like kind of just California.

Josh: Oh, really?

Chuck: Yeah, I mean, it kind of squirted out a little bit there into Arizona some, in the desert, but then other parts of Arizona, obviously, you're going to find it. But most of the country, you can get your poison ivy.

Josh: Except Alaska or Hawaii.

Chuck: Because those are great places. I'm surprised Alaska.

Josh: I'm surprised Hawaii doesn't have it. Everything grows in Hawaii.

Chuck: Yeah, but I don't know, Hawaii doesn't strike me as woodsy, it seems more like-

Josh: Oh, there are a lot of woods there.

Chuck: Lush and palm trees, and like, rainforesty.

Josh: Right, but I mean, this stuff grows in moist areas.

Chuck: Yeah, that's true. I don't know what to think anymore.

Josh: Well, this is the thing: you can't identify it; it grows everywhere, even in the places they say it doesn't grow. I mean, we're in trouble, basically.

Chuck: So the oak-the leaves can also be in threes, but they are thick, green, and hairy on both sides.

Josh: I think the hairy thing is what's the dead giveaway with the family Anacardiaceae.

Chuck: Yeah?

Josh: Yeah.

Chuck: And then the sumac, you're going to find that in swamps or in the Northeast and Midwest along the rivers. It's a woody shrub.

Josh: I love that word, sumac.

Chuck: Yeah, I do too.

Josh: It makes me think of, like, a Native American, just rowing a canoe of their own making down a river.

Chuck: Wow.

Josh: Sumac-that's what it evokes in my mind's eye.

Chuck: That's pretty cool.

Josh: Yeah.

Chuck: And they have stems with rows of 7 to 13 smooth-edged leaflets.

Josh: It doesn't look anything like poison oak or poison ivy.

Chuck: No, and you should know what this stuff looks like pretty much by now, but if you're a city dweller, and you're going to go to the country, look it up online. Just look at some photos.

Josh: Can you identify poison sumac?

Chuck: No, but poison ivy, for sure.

Josh: Yeah, I usually can. Or if I have a question about it, I just assume it is poison ivy and steer clear.

Chuck: Yeah, I don't think I've ever seen the sumac.

Josh: I haven't either, until this article. There's a little-I mean, it's kind of pretty.

Chuck: Oh, that is pretty.

Josh: Yeah.

Chuck: You'll just put your face in it.

Josh: It'll destroy you. So Chuck, I guess-let's stop beating around the bush here.

Chuck: Okay, terrible.

Josh: Yeah. What exactly is going on when poison ivy, and specifically urushiol, comes into contact with your skin? Why do you break out in a terrible, terrible rash?

Chuck: Well, it's pretty much the same-if you remember our allergy podcast, the same kind of thing is going on, from what I can tell. It's like a mistaken response.

Josh: Right.

Chuck: Right? To something that shouldn't give you a rash.

Josh: That's right.

Chuck: Which is why you see animals eating it like crazy and rolling around in it, because they're not dumb humans with dumb immune systems. They're like, "This stuff really is no big deal."

Josh: Yeah, your immune system, when it encounters urushiol, turns into like some bonehead at the bar who's got this heightened response, like, "Don't look at my girlfriend," and wants to fight everybody.

Chuck: Yeah.

Josh: That's what your T cells do in your immune system.

Chuck: Sure.

Josh: So the urushiol, because of the way that it's formed, the compound that it is, it makes it through the skin pretty easily, and as it is absorbed, your body-your skin actually metabolizes it, and breaks it up into little components, and presents it to your T cells, your immune system cells, to say, "Are these guys cool? You recognize these guys?" And again, your T cells are like, "What? No. I want to fight this guy." And he calls his boys, the cytokines, right?

Chuck: Yeah.

Josh: The cytokines come along, and they're like, "Yeah, let's fight."

Chuck: Yes, get those white blood cells because they are some tough dudes.

Josh: Right, and the white blood cells come in, and they're huge, and they turn into macrophages.

Chuck: That's right, and they eat stuff; they eat the foreign substance like crazy. And in doing so, that's where you get your rash. It damages the tissue.

Josh: Yeah, because they're not just focusing on the urushiol.

Chuck: No, because they're dumb.

Josh: They're indiscriminately just messing the whole place up, the whole bar just goes to pot because there's like glasses broken and stools thrown, and everything is just messed up.

Chuck: Yeah, it's like the movie Hooper.

Josh: With-?

Chuck: Burt Reynolds.

Josh: Really? Yeah, I haven't seen that one.

Chuck: One of the great bar fights of all time.

Josh: Oh, I got to see it then.

Chuck: Yeah. So that's what's going on, basically. That's where the inflammation comes from. It is just like in allergies with hay fever; it's a mistaken response to that pollen, in hay fever's case. And it's just your dumb body not knowing that it really shouldn't be a big deal.

Josh: Exactly, which is why, over time, over repeated exposure to poison ivy, even those lunkhead T cells figure out, "Oh, you're a pal. I don't have to mess with you."

Chuck: Right. "I know my girlfriend is pretty. It's cool. I'd look at her, too."

Josh: Right, they calm down over a while.

Chuck: Yeah.

Josh: So eventually, I guess if you just rubbed poison ivy on yourself enough times, your response wouldn't occur at all.

Chuck: Yeah, but there is a myth that you can eat poison ivy to develop that immune response.

Josh: Do not do that.

Chuck: Don't do that, because you could die, quite seriously.

Josh: Right, so what we just described can happen on your internal organs rather than your skin; the macrophages come in and indiscriminately just start eating everything and damaging the tissue. That's one thing if it's on your arm. It's another thing if it's on your esophagus.

Chuck: Sure.

Josh: You know?

Chuck: Yeah, the thing could swell shut.

Josh: Or, just as bad, your lungs, too, which is another reason why when you destroy poison ivy, you don't burn it, because when you burn it, the urushiol vaporizes, and you can inhale and that's really, really bad.

Chuck: That is really bad. You mentioned that you thought you were okay after a few minutes. There can be something called delayed hypersensitivity.

Josh: It is that.

Chuck: It's always that.

Josh: Yeah.

Chuck: Because you're not going to rub it on your skin and get it seconds later. That's immediate hypersensitivity. If you have delayed hypersensitivity, it could take hours, it could take days. You might think you're all good, and a few days later, you're going to get it, which is one of the reasons the myth of "if you scratch, it'll spread it" happens, because you might see it popping up on other parts of your body days later, and it's not from scratching or spreading; it's because just that delayed response.

Josh: That's right.

Chuck: Yeah, but you know more about that, right?

Josh: Yeah, so the whole thing-what we found out people call poison ivy, the rash, is technically called allergic contact dermatitis, and you can get it from all sorts of things, like laundry detergent, or like an itchy tag. It's basically a skin irritation from an allergic reaction, and with the delayed kind, yes, it takes anywhere from hours to days, but it's going to happen. There's also immediate, which is like, say, a bee sting, or a peanut, where you eat it and within minutes, you're in big trouble. And actually if you do start to display the same kinds of symptoms that you would with an immediate reaction, you really need to go to the hospital. Like if your throat swells up from poison ivy, or your lips turn blue from poison ivy, or you have a fever that's over 100 degrees from it, those are all signs that you need to go to the hospital. This isn't a normal reaction to poison ivy.

Chuck: Yeah, if your lips turn blue at all in life, go to the hospital.

Josh: Yeah.

Chuck: That's just Dr. Chuck chiming in.

Josh: So we're going to bust some more myths and all that kind of jazz right after this.


Chuck: You know, buddy, some say that we humans spend 90% of our life in our underwear.

Josh: It makes sense. I've got some on right now.

Chuck: I do, too, actually.

Josh: That's good, Chuck.

Chuck: Because it's Tuesday; it's underwear day. But you know when you have that old underwear and it's saggy and the waistband is all stretched out and it's just not soft anymore?

Josh: Yeah, underwear gets worn out, I guess is another way to put it.

Chuck: It's gross, but we have a solution. It's called

Josh: That's right. MeUndies is the most comfortable underwear you will ever wear, and it is insane how good they make you feel. They fit perfectly, they don't ride up, they literally pull moisture away from your skin so you stay cool. It's the perfect underwear.

Chuck: That's right, buddy, because I'm wearing them right now, and I am staying cool in all the right places, and in fact, I feel like I'm floating on a pillow of air.

Josh: That's fantastic, Chuck.

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Chuck: That's right. And they're going to guarantee you're going to be happy with them, or your first pair is free. Once you feel the MeUndies on your body, you're never going to go back.

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Josh: Okay, so Chuck.

Chuck: Yes?

Josh: I said that we would bust some more myths.

Chuck: That's right.

Josh: Let's do that.

Chuck: Okay.

Josh: So one of the things you said is that poison ivy doesn't spread. Like if you have it-remember when I had it?

Chuck: Yeah.

Josh: If I brushed up against you, you wouldn't have gotten poison ivy, unless I had some urushiol on my skin.

Chuck: Correct.

Josh: So the poison ivy rash itself is not contagious.

Chuck: No, but if it still on your body, you could spread it, like if I was-if you and I were in one of our famous camping-hiking retreats.

Josh: Sure, yeah.

Chuck: And we were in the woods, and I got it on my hand, and then slapped you on the back and told you what a good pal you were, and of course you hike shirtless, so you might get it because I actually have the compound on my hand.

Josh: If it could make it through the thick matt of hair on my back, then yeah, I might catch poison ivy from that.

Chuck: Well, you're hairy on both sides just like the poison oak.

Josh: [LAUGHS] Right. That's right.

Chuck: But let's say you do come into contact; you're out in the woods, you're camping and you know. You're like, "Oh, man, crap. I've been avoiding it, but I just got it all over my foot, and I realize I did that." What you want to do is just act super fast; get it in the creek, or wash it off if you have water-immediately with just plain water. The quicker you do it, the better your chances of not having that response.

Josh: And you also want to use cold water, too; warm water is going to open your pores, which will allow the urushiol to be absorbed that much faster.

Chuck: That's no good. Apparently warm-or hot water will help after you've gotten it, though, with the itching symptoms.

Josh: Right, yes.

Chuck: Like a really hot shower, but not at first. You rinse off that skin, take off all your clothes that have come into contact with the plant, and you're going to wash those as quickly as possible, as well. So now you're naked out in the woods. You're naked and afraid. You're washing your clothes. You want to wash your skin at that point with the soap and water.

Josh: After you've already washed it off initially.

Chuck: Yeah, rinsed it, and then if you have-if you're at home, get some isopropyl alcohol and cotton and then do that next. If you're out in the woods, you probably won't have that.

Josh: Yeah, so like you said, if you act fast, you might be able to prevent a reaction, and that's because you are washing the urushiol off before your skin absorbs it.

Chuck: Yeah.

Josh: Once your skin absorbs it, you have a very limited amount of time to take some sort of steroid, like a corticosteroid, that actually reduces the body's immune response naturally. An antihistamine is a good example of that.

Chuck: Yeah, or a topical. If you're super allergic, you may even have a prescription for something like this, which you want to take right away, but if not, just get the Cortaid or Lanacort and rub that all over your body like my dad did, and look like a weird pink beast.

Josh: Right, but the problem is, these windows close pretty quickly, because once the urushiol is absorbed, and once your body mounts this immune response, once those macrophages go in and do all this tissue damage-

Chuck: You're dead.

Josh: Your body has to heal from that, no matter what, even if your body is no longer responding to this foreign invader that's actually harmless, the damage is still done and you've got yourself this dermatitis that you've got to deal with.

Chuck: Yeah, and it's going to itch, and you shouldn't scratch it, not because you'll spread it, because you can actually get infected. And I don't remember-did you scratch a lot?

Josh: Oh, yeah.

Chuck: Or were you pretty good about it?

Josh: I mean, I wanted to.

Chuck: What were some of your little-I know when someone is infected like that with something, as an adult they do all kinds of things, like, "I'm not scratching, I'm just rubbing my face on my pillow super hard."

Josh: Right, no. I used a lot of self-control, a lot of smacking.

Chuck: Oh, yeah, yeah.

Josh: You can smack the thing and it won't scratch, and the whole reason you're not scratching is not-again, you're not going to spread it by scratching, but what you're going to do, conceivably, is you're going to open up these sores.

Chuck: Yeah, because they can get full on blisters.

Josh: Right, and if you break one of these blisters and you've got poop under your fingernails, you can infect the blister and get a skin infection, and end up with scars. It's not a good jam. So if you smack it, you're not going to scratch it or you're not going to break the skin, but you can still alleviate that itch that's generated by your skin repairing itself.

Chuck: Because you never know when you might have poop under your fingernails.

Josh: Exactly.

Chuck: So just defer to the smack.

Josh: I'll bet there's a substantial amount of the population who has poop under their fingernails at any given point in time.

Chuck: Yeah, I don't want that weird stat, not at all. So a hot shower once you have the rash can help soothe itching a little bit. Calamine lotion can help. Baking soda paste, if you're into more natural things.

Josh: Sure.

Chuck: Baking soda and water just mixed together, basically-rub that on there. And the old oatmeal bath with any kind of rash will soothe things a little bit.

Josh: That's right. I think I used just tons of calamine lotion, if I'm not mistaken. I think I blocked a lot of that out.

Chuck: And would Umi just walk by shaking her head at you every time she saw you?

Josh: She took good care of me, but yeah. Yeah.

Chuck: That's good.

Josh: You can also just kind of get around the whole thing by using something like IvyBlock, which uses something called-

Chuck: Oh, that's like if you go camping and you know you're allergic, you can take something beforehand?

Josh: That's right.

Chuck: A preventative, that's what it's called.

Josh: Yeah, bentoquatam.

Chuck: I've never heard of that.

Josh: Or bentoquatam. Basically, it acts as a shield. It prevents the urushiol from being absorbed by your skin.

Chuck: Interesting.

Josh: And it works to a degree, supposedly.

Chuck: If you do want to get rid of it at your house, you should do what Josh did, sort of, in that you wore boots and long sleeves and gloves, and all that stuff. So you were on the right track.

Josh: Just don't gaze upward in wonder as the stuff falls down onto your face.

Chuck: Mouth agape. [LAUGHS]

Josh: Man, that was just bad.

Chuck: Not good, but if you do dress up like that and cover yourself, you want to pull it out by the roots, get it all out of there, and-

Josh: Because it's a vine, and vines can establish themselves pretty easily with just the slightest fragment of living plant.

Chuck: That's right.

Josh: And don't burn it.

Chuck: No, no, no.

Josh: It's not just bad news for you, it's bad news for all your neighbors, too.

Chuck: Yeah, I imagine.

Josh: You got anything else?

Chuck: Old Man Clark over there is burning his poison ivy again.

Josh: [LAUGHS] Right.

Chuck: I got nothing else.

Josh: I don't either. That's poison ivy. If you want to know more about it, including seeing pictures of poison ivy and poison sumac and poison oak before you go camping, you can type in poison ivy at the search bar at, and it will bring up this great article, and since I said search bar, it's time for listener mail.


Chuck: I'm going to call this part two of scientific method, from a scientist. "Hi, Josh, Chuck, and Jeri, J-E-R-I, I feel like I'm not getting her name right." So I'm sensing that these scientists are-they don't feel good about their spelling abilities.

Josh: No, but they're doing a great job.

Chuck: They are. "Just heard the episode on the scientific method and wanted to say you guys did a pretty good job with it and its history, and I say this as a practicing scientist." And he had a great long email, but I'm going to have to edit for content, but he talks a little bit about the woes of current science. He said, "It is a problem that many young academics fret about. The problems are real, but I want to underscore the fact that in many ways, it is a golden age of science right now. So much good work is getting done. It just happens to be a terrible time to be a scientist. More funding would help alleviate some of the strain academia is under, but as you point out, there's some systematic reforms that need to happen, as well, and many are discussing just what a workable solution is. I have tried to stick as close to the scientific method as possible in my career, and haven't been all that productive because of it. I'd rather publish something solid than put something out there that's potentially wrong or flawed. Being able to publish negative data would be good, but even more to the point, science almost works well as improv, which is the 'yes and' approach, where a scientist proposes a hypothesis and supports it, and another scientist picks it up and says, 'Well, yes, if so, than this should also be true, as well,' and extends the original work." So he's a collaborator. "The scientific method is a huge part of our lives and needs to be taught to all. I say we need more science literacy, not more scientists, but it can be tricky. Science and nature are truly amazing, and yet we're not willing or able to support all those who'd want to make it a career." He gives us a cheers. That is Ian Street, Ph.D.

Josh: Nice job, Ian. That was a great email.

Chuck: Yeah, and good for you for sticking to the scientific method even to your detriment.

Josh: Yes.

Chuck: Hang in there. I hope you write a great paper one day that gets you accolades and money.

Josh: With great spelling, too.

Chuck: That's right.

Josh: If you want to be like Ian and talk to us, you can tweet to us @SYSKPodcast, you can join us on, you can send us an email to, and as always, you can join us at our home on the web,


Vo: For more on this and thousands of other topics, visit


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