SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/hike-poison-ivy-oil

What substance on poison ivy causes the rash?

Urushiol oil causes the skin reaction.

Start playing free

  1. Urushiol oil ✔
  2. Pollen grains
  3. Sap sugar

Why: Urushiol is an oil in the sap of poison ivy, oak and sumac. It sticks to skin, clothes, tools and pets until it is washed off.

Huh, didn't know that: Wash your skin with soap and cool water as soon as possible after touching the plant.

The dad joke
Why did the urushiol oil make friends easily? It really stuck to people.
Like this card?
Play the game

References

Answer: Urushiol oil. Urushiol is an oil in the sap of poison ivy, oak and sumac. It sticks to skin, clothes, tools and pets until it is washed off.

  1. FDA: Outsmarting Poison Ivy and Other Poisonous Plants www.fda.gov/consumers/consumer-updates/outsmarting-poison-ivy-and-other-poisonous-plants
    The culprit: the urushiol oil.
    Checked 2026-10-12.

Think this answer is wrong? Tap "Challenge this answer" on the card in the game and tell us why.

Test yourself in the game

Outdoors & CampingWhich group first came up with the Ten Essentials packing system for hikers?Outdoors & CampingWhy does the Park Service recommend a headlamp over a regular flashlight for hiking?Outdoors & CampingHow much extra food does the Park Service suggest packing as one of the Ten Essentials?

That's stuff everyone should know.