Urushiol

Urushiol is any of several chemicals found in plants of the family Anacardiaceae, especially Toxicodendron, such as poison ivy, and causing the rash on contact. It is named for urushi[?], a lacquer produced by Japanese from the sap of Toxicodendron trees called kiurushi. Chemically it is 1-alkyl phene-2,3-ol; the alkyl group has 15 or 17 carbons and may be unsaturated, depending on species.

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