Have you ever heard this old saying? “Leaves of three? Let them be!” If you haven’t, it’s good advice! Knowing how to recognize poison ivy can make a camping trip or any outdoors adventure much better.

Toxicodendron radicans — more commonly known as poison ivy — is a poisonous plant known for the itching rash it can cause. The sap within the plant contains a clear liquid called “urushiol.”

It’s the urushiol that causes the allergic reaction that up to 80 percent of people experience after exposure to poison ivy.

Poison ivy is not really an ivy at all. However, its appearance resembles ivy. Found all over the United States, poison ivy can be difficult to identify at times.

Poison ivy can be found growing in three different forms: a trailing vine, a shrub or a climbing vine that grows on trees, fences, buildings, etc. It can be found anywhere, from your backyard to the woods to the sides of highways.

Poison ivy blends in well with other plants, so you have to be careful when you’re hiking in the woods or walking anywhere with a lot of plants.

If you’re wondering whether a plant is poison ivy, look for these clues:

1. clusters of three leaves (“leaves of three”) 2. shiny (not fuzzy) leaves that are smooth
3. no thorns

Poison ivy can look different depending on the season. Leaves that start off red or light green can turn darker green as they mature, before turning red, yellow or orange in the fall.

Two other poisonous plants that also contain urushiol are poison oak and poison sumac. Keep an eye out for these plants, too!

Poison ivy can also be hard to identify because there are many plants with “leaves of three.” If you’re not sure, don’t touch it. It’s best to play it safe when it comes to poison ivy!

So what should you do if you suspect you’ve come into contact with poison ivy? Wash your skin with soap and water as soon as possible. If possible, take a hot, soapy shower.

The urushiol oil is what causes an allergic reaction when absorbed into your skin. If you can wash it off soon enough (within 10 minutes of contact), you may be able to avoid an allergic reaction and a bad, itchy rash.

You should also wash any clothes, shoes, garden tools or pets that may have come into contact with poison ivy. Urushiol oil on your clothes, your shovel or your dog can cause a rash if you touch them later.

The oil can stay on unwashed items for a very long time. It’s not uncommon to get a poison ivy rash from shoes that you may have worn when you stepped on poison ivy last summer!

Once you have an allergic reaction to poison ivy that turns into an itchy rash, there’s not a whole lot you can do other than treat the skin and try to minimize the discomfort. Cold showers and calamine lotion can help, as can oatmeal baths. More serious cases may require a visit to the doctor to get an antihistamine or steroid shot to decrease itching and swelling.

Contrary to the beliefs of many, the oozing fluids that are sometimes released from the blisters caused by poison ivy do not spread the poison. Urushiol is the only thing that can cause the allergic reaction.

Once it binds to your skin, it is absorbed and cannot be transferred to another person. So, once you shower after being exposed to poison ivy, it’s not contagious and can’t be passed on to another person.

Curiously, people sensitive to poison ivy sometimes experience a similar rash from mangoes. Mangoes are in the same family as poison ivy, and the sap of the mango tree and the skin of mangoes contain a chemical similar to urushiol.


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  1. Rise and shine, HAPPY CAMPERS! Today is the first day of Camp What-a-Wonder!

    We are so excited to have you here at camp! We’ll be learning a lot together over the next few weeks, so be sure to leave us a comment today and let us know how you’re enjoying yourselves! :-)

    • We’re really sorry to hear that, kerrickelementray/ebd/class! We hope it wasn’t too itchy or painful. Thank you for visiting Wonderopolis today and for leaving us a comment! We hope you’ll come back for more Camp What-a-Wonder fun this summer!

  2. Yay!!! One of my predictions was right!!! My dad is Allergic to poison ivy, so it’s really bad when he gets it. I usually stay out of the woods behind my house, so I don’t get poison ivy that much.

    Is camp What A Wonder, the exciting new event MC was talking about? I think that is sooo cool!! Are most of the wonders going to be about the outdoors, now?

    I think that tomorrow’s wonder is about cats, lions, or tigers. I can’t wait to see!!! :D

    • We know how SUPER smart you are, Meredith…you’re also VERY good at guessing! Way to go! :-) We think staying away from poison ivy is a VERY smart idea, too!

      Yes, Camp What-a-Wonder is our new summertime learning experience here in Wonderopolis! We’re sooo glad you like it! Each Thursday during the summer, Wonderopolis will transform into Camp What-a-Wonder and we will have LOTS of fun while we’re learning new things! :-)

  3. What is this all about? I don’t get this and I hope you have a good care of what you are doing and
    you should have people not be in poison and y’all shouldn’t have poison in this world.

    • Hi there, kerrickelementray/ebd/class! Welcome to Wonderopolis! Every day, we have a new Wonder of the Day® to learn about a new, fun, exciting thing!

      Today is a special Thursday, because it’s our first day of Camp What-a-Wonder! Every Thursday this summer, we’ll be having extra camp-focused fun! You can visit Wonderopolis any day you like, though, and you’ll always find something new to WONDER about!

      We would never want any of our Wonder Friends to have poison ivy. Today’s Wonder of the Day is about learning how to spot poison ivy so you can keep yourself and your family and friends safe! Thank you so much for your comment today! :-)

    • Thanks, Abby! We knew we could count on all of our AWESOME Wonder Friends to be GREAT What-a-Wonder Campers, too! :-)

  4. I unfortunately have already gotten into poison ivy,oak, or sumac. I am now on meds after a week and a half of misery. This is the worse case I have every had. I would love to see pics of the three to disseminate. Thanks. I think this site is great!

    • Yikes, Just Me! That sounds awful. We’re super sorry you had a run-in with one of those poisonous plants! Here is a link to a page from the Centers for Disease Control and Prevention that shows photos and give descriptions of poison ivy, poison oak, and poison sumac: http://www.cdc.gov/niosh/topics/plants/

      Thanks for visiting Wonderopolis! We hope you feel better soon! :-)

  5. Hooray so many WONDER friends are attending camp. I am so excited for my MC friends! I am looking forward to the campfire tonight on twitter at 8:00 I got my smores all ready to go.

    • We are VERY happy that so many Wonder Friends (including one really awesome teacher we know) have visited and commented today, Maria! :-)

  6. Thank you so much for providing a great way for families to fight back against summer slide! My students love Wonderopolis and will be excited to discover this fun resource. Keep up the GREAT work! :D

    • Hi there, Ms. Gannon! Thanks for your kind words! We are so happy to hear that your students love Wonderopolis, and hope that they will share what they like and learn from their favorite Wonders of the Day! :-)

  7. so cool…can’t wait for the campfire. I never knew what poison ivy looked like. “Never been there – not gonna do that!” (fingers crossed)

    • We hear you, Jon! “Leaves of three, let it be!” Thanks for your great comment and for being such an awesome Wonder Friend! :-)

    • Thanks for visiting Wonderopolis, Dave! We think geocaching sounds like so much fun! What a great activity to share with family and friends! :-)

    • We’re glad you learned something new from this Wonder of the Day®, Jaden! Thanks so much for stopping by Wonderopolis today! :-)

  8. We’ve been to a forest before with poison ivy. My brother got poison ivy but I did not. But my brother is cured from the poison ivy now!

    • Phew, you really are one lucky duck, Skye! We’re also VERY glad to hear that your brother isn’t affected by poison ivy any longer! We hope you learned how to stay away from that itchy plant, Wonder Friend! Thanks for sharing your comment! :)

    • We bet it would be a lot of fun to create a Wonder Book of your own, Anne Anne :D! You can write down Wonders of your own and do some research of your own to find the answers! We bet your book would be AWESOME! Thanks for sharing your comment with us! :)

    • YIKES, we hope you stay poison-ivy-free, Wonder Friend Chase! It’s a good thing you know to stay clear of that sly leaf! Thanks for sharing your connection to our Wonder! :)

    • You are welcome, Sue. Thanks for visiting Wonderopolis and leaving us a comment! We hope have a WONDERful, poison ivy free weekend! :)

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Have you ever wondered…

  • What does poison ivy look like?
  • Is a poison ivy rash contagious?
  • How do you treat poison ivy?

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