Toxicodendron radicans, commonly known as eastern poison ivy or poison ivy, is a poisonous Asian and North American flowering plant that is well-known for causing Urushiol-induced contact dermatitis, an itchy, irritating, and sometimes painful rash in most people who touch it. It 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). Toxicodendron 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.