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Closeup of poison ivy leaves on the side of a trail

Poison Ivy vs. Oak vs. Sumac

You can recite the adage by heart, “Leaves of three, let them be.” So, that means you’re ready for your outdoor adventure, right? Well, no. Like most everything else in life, it’s not quite that simple. Lots of plants have “leaves of three,” and they’re not all poisonous. So, what do you need to know to stay itch-free?

Ohio’s Itchiest Plants

Description and sketch of poison ivy

Poison Ivy

Unfortunately, this one’s not so easy. Poison ivy is very common in Ohio. It can grow like a vine or ground cover, and can even get you itching in the winter when it has no leaves. Poison ivy contains a chemical called urushiol that causes an itchy rash. Obviously, you can get poison ivy by touching the plant directly, but you can also get it by touching something else that came into contact with it — like your dog. It usually takes about 24 hours for the rash to show up, and a few weeks for it to go away. Surprisingly, the rash is not contagious.

What Should I Do?

If you come into contact with poison ivy, wash your skin immediately using dish soap and COLD water (warm water can actually cause the urushiol to penetrate deeper). You can also clean the area with rubbing alcohol. You’ll want to be sure to wash your clothes or any other item that may have come into contact with the plant as well.

What Does It Look Like?

Poison ivy has leaves that grow in groups of three. The middle leaf has a longer stem than the two side leaves, and there may be small white or yellow flowers attached. The stem looks like it has tiny hairs growing out of it. In the winter, there may be just a vine, or a vine with white berries. In the spring, the leaves start out red and then turn green. They stay green all summer and then change to red or orange in the fall.

Description and sketch of poison sumac

Poison Sumac

Poison sumac is considered the “most toxic plant in the country.” However, on a positive note, it’s also much rarer than the others. It only grows in super wet areas, like bogs or swamps. Just like poison ivy, sumac also contains urushiol. That means it causes the same reaction as poison ivy — an itchy rash.

What Should I Do?

The same rash as poison ivy, caused by the same chemical as poison ivy, means you should use the same protocol. Wash right away using the instructions above.

What Does It Look Like?

Poison sumac can look like a bush or even grow into a tree. It has red or brown stems that grow clusters of about 10 leaves each. Except for the leaf at the tip of the stem, the leaves grow in pairs opposite one another. Leaves are green in the spring and summer, but change color and fall off in autumn. There may be clusters of white berries hanging from the branches during the winter.

Description and sketch of poison oak

Poison Oak

Well, let’s start with the good news. Poison oak doesn’t grow in Ohio. So, check that one off your worry list! It’s most commonly found in the southern and western United States.

Preventing and Treating Exposure to Poisonous Plants


Avoiding contact with poisonous plants is obviously the best way to prevent “the itch.” And now that you know what you’re looking for, that should be a lot easier. However, sometimes those plants can sneak up on you. To lessen your chance of direct contact:

  • Wear long sleeves and pants to keep your body covered.
  • Walk on cleared paths.
  • Be sure to remove any poison ivy or sumac that’s growing in your yard. NEVER burn the plants. Inhaling the smoke can cause a severe allergic reaction.
  • Keep your dog out of wooded areas.
  • Consider applying a poison ivy/sumac barrier cream.
  • Wash yourself and anything that may have come in contact with a poison plant right away.


If you develop a poison ivy or sumac rash, you can help calm the itch with:

  • Antihistamine
  • Cold compress
  • Hydrocortisone cream
  • Oatmeal bath

See your doctor right away if:

  • Rash/blisters spread to your mouth, face or genitals
  • You have a wide-spread rash
  • Your rash lasts more than a few weeks
  • You think your blisters may be infected

Call 911 immediately if you have:

  • Trouble breathing or swallowing
  • Swelling, especially on your face
  • Itching over most of your body and you can’t get relief


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