Toxicodendron radicans, commonly known as eastern poison ivy or poison ivy, is an allergenic flowering plant that occurs in Asia and eastern North America. The species is well known for causing urushiol-induced contact dermatitis, an itchy, irritating, and sometimes painful rash, in most people who touch it. The rash is caused by urushiol, a clear liquid compound in the plant's sap. The species is variable in its appearance and habit, and despite its common name, it is not a true ivy (Hedera), but rather a member of the cashew and pistachio family (Anacardiaceae). T. radicans is commonly eaten by many animals and the seeds are consumed by birds, but poison ivy is most often thought of as an unwelcome weed. It is a different species from western poison ivy, T. rydbergii, which has similar effects.