Stinging Nettles Native plant that causes stinging and burning when touched. How toxic is it? Usually Non Toxic Mildly Toxic Highly Toxic When touched, the hairs on stem and leaves produce burning, itching, and inflammation of the skin. Which may last for several hours. Contact the poison center to discuss treatment options. Call 1 (800)-222-1222 Text 206-526-2121 Chat with a Poison Specialist Common brands & formats What to do If on skin What to do: Most exposures are treated with topical lotions and resolve within hours.