Answer: urushiol

AnswerCrossword Clue
URUSHIOLIrritant in poison ivy
urushioltoxic, liquid, catechol derivative, the active irritant principle in several species of the plant genus Rhus, as in poison ivy
urushiola mixture of catechol derivatives with saturated or unsaturated side chains of 15 or 17 carbon atoms that is an oily toxic irritant principle present in poison ivy and some related plants (genus Rhus) and in lacquers derived from such plants
urushiola toxic liquid