urushiol

plural urushiols

1. countableuncountablechemistryAn oil found in plants of the family Anacardiaceae, causing an allergic skin rash on contact; consists of a variable mixture of several related organic compounds.

   Upon exposure to air, urushiol can turn dark brown, which makes it easier to spot.

   2000, C. Franklin Goldsmith, Shannon E. G. Hamrick, H. James Hamrick, The Best Hikes of Pisgah National Forest

   2 more examples

   All three produce an oil, called urushiol, that is a potent allergen. Urushiol is most abundant in the leaves and stems of these plants...

   1986, Francine Brown, Skin Care

   Poison ivy vines also contain the irritating oil urushiol, so it is important to be able to recognize them in winter.

   1993, Jacquelyn G. Black, Microbiology: principles and applications

   Synonyms: toxicodendrol