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.