Tecnu Extreme® Poison Ivy Scrub is different from other products on the market in two ways. First, it gets to the root of the problem by removing an ultra-potent and toxic substance called “urushiol” (ooh-roo-she-all) from the skin. Urushiol comes from the poison oak, poison ivy and sumac plants and attaches to the skin. It is the source of the poison ivy rash, irritation and spreading. In addition, Tecnu Extreme contains an active ingredient to relieve itching fast!