Poison ivy (Toxicodendron radicans) is a vine that contains an oily resin known as urushiol. According to the Centers for ...

Poison oak is similar in appearance to poison ivy but is usually found as a shrub rather than a vine. It can have clusters of three, five, or seven leaves, which resemble oak leaves—hence the name.

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An curved arrow pointing right. Only 10% to 20% of Americans aren't allergic to poison ivy's rash-inducing oil, urushiol. Rising atmospheric carbon dioxide levels are causing poison ivy leaves to ...

When you’re spending time outdoors this summer, in your own yard or hiking in a park, it’s useful to know to spot poison ivy.