Toxicodendron radicans, commonly known as poison ivy, is a plant that can cause allergic reactions in many people. It contains an oil called urushiol, which can lead to skin irritation, rashes, and blisters upon contact. The plant typically grows as a vine or shrub and is found in various habitats across North America. Identifying poison ivy is important for avoiding allergic reactions. It usually has three leaflets, with the phrase "leaves of three, let it be" serving as a helpful reminder. The plant can change appearance with the seasons, displaying green leaves in summer and vibrant red or orange foliage in fall.