poison ivy: Media

plant

Videos

Why does poison ivy make people so itchy?
Learn how the oil urushiol, secreted by poison ivy (Toxicodendron radicans),...
Video: © American Chemical Society (A Britannica Publishing Partner)
Why scratching an itch actually makes it worse
Understanding the chemical process of itching and why scratching is futile.
Video: © American Chemical Society (A Britannica Publishing Partner)

Images

Poison ivy (Toxicodendron radicans)
Walter Chandoha
allergy
An allergic contact dermatitis reaction caused by exposure to poison ivy.
© Joy Brown/Shutterstock.com