Environment Planet Earth This Plant's Excruciating Sting Can Drive Humans Mad By Kimberley Mok Kimberley Mok Twitter Writer McGill University Cornell University Kimberley Mok is a former architect who has been covering architecture and the arts for Treehugger since 2007. Learn about our editorial process Updated March 31, 2022 Share Twitter Pinterest Email Photography by Mangiwau / Getty Images Environment Weather Outdoors Conservation While there are plenty of plants that we enjoy as superfoods, use as building materials, or plant to attract beneficial pollinators, there are some plants we would do well to stay away from. Take the innocuous-sounding and innocent-looking gympie-gympie (Dendrocnide moroides), of the nettle family Urticaceae. This green, leafy bush has heart-shaped foliage and is found commonly in rainforested areas in northeastern Australia, the Moluccas, and Indonesia. But beware; it is covered with hollow, hair-like, stinging needles that contain a powerful neurotoxin that causes excruciating pain. The extreme itching is so painful that it has been known to kill dogs and horses, and to even drive humans mad with agony. Effects of the Neurotoxin The gympie-gympie's active compound, moroidin, is so persistent that it has been known to torture its victims for over a year if its stinging hairs are not removed from the skin. Even dry specimens, preserved for many decades, can still retain their powerful sting. Here's how virologist Dr. Mike Leahy explains gympie-gympie's deadly effects: The first thing you’ll feel is a really intense burning sensation and this grows over the next half hour, becoming more and more painful. Shortly after this, your joints may ache, and you might get swelling under your armpits, which can be almost as painful as the original sting. In severe cases, this can lead to shock, and even death. Stories abound of gympie-gympie's notorious side effects. Stung horses have been known to die within hours. One man was purported to have shot himself to end his pain after inadvertently using the leaves as toilet paper. Even inhaling floating hairs can cause sneezing, rashes, and nosebleeds. Entomologist and ecologist Marina Hurley, who studies various Australian stinging trees, has likened gympie-gympie's effect to "being burnt with hot acid and electrocuted at the same time." Yet remarkably, there are some marsupial species, insects, and birds that consume the plant's leaves and fruits with no problem. Hurley shows us the plant in this excerpt from the French documentary "Plant Secrets": Remedy So what is the remedy for gympie-gympie's sting? The most effective treatment is pretty simple. Do not rub or scratch the area—you do not want to break off the offending hairs and make them harder to remove. Visible hairs can be removed with tweezers, and adhesive tape or hair-removal wax strips can be used to remove the more delicate hairs. The gympie-gympie plant is a clear example that even the most innocent-looking things can pack a powerful punch and that we should never underestimate the power of nature. View Article Sources "Stinging plants." Australian Government Department of Health.