Itch weed is the common name for the stinging nettle, a perennial herb with pinkish, heart-shaped flowers and bristly protrusions on its stem and leaves. The plant flourishes throughout the United States, along roadsides, near mountains and in forest areas.
The hairs on the stinging nettle are hollow and contain toxic chemicals, such as histamine and formic acid, a substance also present in ant venom. Stings from this weed cause irritant dermatitis and an intense itch that can last up to 12 hours. Jewelweed soap or lotion soothes the pain of nettle stings. Native Americans in the Northwestern United States used stinging nettle fibers to make rope and fishing nets.