Gympie Poisoning

Medically Reviewed by Mahammad Juber, MD on December 16, 2022
6 min read

Australia is known for its multitudes of dangerous insects and animals, and it’s also home to some of the most painful plants in the world. This includes two species of stinging nettles that commonly go by the name gympie — or, the gympie gympie plant. 

Contact with these plants can lead to intense pain and swelling that lasts anywhere from days to months. Learn how to recognize these plants, or you could end up spending your Australian getaway in an emergency room.

The name gympie gympie could refer to one of two very similar species of plants in the Dendrocnide genus — D. moroides or D. excelsa. Both of these plants are in the Urticaceae family which contains over 150 species of stinging plants. These two similar species are both considered stinging nettles. 

Gympie is such a notorious plant that it goes by a number of common names, including: 

  • Gympie stinger
  • Gympi gympi
  • Mulberry leaved stinger — this specifically refers to D. moroides
  • Giant stinging tree — this specifically refers to D. excelsa 

D. moroides is a shrub. D. excelsa is a large tree. They both have underground root systems and above-ground trunks with branches, leaves, and — at certain times of year — flowers, fruits, and seeds. The stinging nettles grow on most of the plants’ above-ground structures. 

These plants don’t have any current uses in either medicine or cooking, but they are a great source of nutrition for the white nymph butterfly’s larvae.

Gympie gympie can be found within the rainforests of Australia and some parts of Southeast Asia. This plant prefers disturbed areas where there’s plenty of sunlight. 

D. moroides and D. excelsa look incredibly similar. The main differences are in their heights and the way that their leaf stalks are positioned. 

D. moroides is shorter and more shrub-like. It reaches an average of four meters — approximately 13 feet. Its stalks attach at a point that’s away from the margin of the leaf. 

D. excelsa can grow up to 35 meters — approximately 115 feet. Its leaf stalks attach near the margins. 

Otherwise, the two species are nearly identical in terms of both their looks and their threat level. Pay attention to the leaves to help with gympie gympie identification. They have heart-shaped leaves with fine, jagged teeth on the edges. These leaves are commonly riddled with holes and other evidence of insect damage

These plants form small flowers that sprout between the leaves on a short stalk called an inflorescence. The flowers are white or purplish, and the inflorescences can be up to six inches in length. The flowers could be present at all times of year but are more common in the summer. 

Once the flowers are pollinated, their stalks swell up into fleshy purple structures that resemble fruit. One fruit from each cluster forms a small, hard seed. 

The leaves, flowers, and most of the rest of the plant are covered in minuscule stingers. The stingers are made of silica and considered modified trichomes — a special, hair-like tissue that forms on the outside of plants. These stingers are so small and dense that they make the plants look soft and fuzzy. Juvenile leaves have more stingers than adult leaves.

Gympie gympie plants are poisonous. The main gympie gympie poison is a neurotoxin that causes enormous amounts of pain. It’s contained within the plants’ stingers. 

The stingers are small, but they easily burrow into your skin — even if you only lightly graze the plant. In fact, they’re so small that your skin can easily close over them and seal them in. 

Then, the stingers act like very small hypodermic needles and inject a liquid that contains a large number of chemicals. For the two species of gympie described here, the most problematic of these chemicals are small, stable proteins named gympietides. 

These proteins remain stable the same way that the toxins used by certain spiders and cone snails remain stable. It’s a fascinating example of a phenomenon called convergent evolution. Convergent evolution occurs when the same mechanism evolves separately in very distantly related species — in this case, between entirely different biological kingdoms.

The effect of your gympie gympie poisoning depends on how much contact you had with the plant. The more that you touch it, the more neurotoxin you receive, and the worse your reaction will be. 

The first symptom that you’ll experience is immediate and intense pain or stinging wherever you touched the plant. Then, red bumps or white spots will form, and the surrounding tissue will flood with lymph fluid. This causes the area to swell up. You may also start sweating. 

You may experience pain and tingling in distant parts of your body. This includes your armpit and groin — where major lymph glands are located. One affected person also reported stinging in their feet that lasted for days even though they’d touched the plant much higher up on their body. 

If the stingers get into the air, you could also find yourself sneezing a lot and producing a large amount of mucus. 

Mild symptoms could clear up in a few days, but more severe injuries could remain sensitive for weeks or even months.

Most people who come into contact with gympie gympie don’t need to rush to the emergency room, but some people are in so much pain that they feel compelled to seek out medical attention. Unfortunately, there’s little that medical staff can do to help. In some cases, the pain doesn’t even respond to morphine

The only time that you truly need to get emergency medical help, though, is if contact with the plant triggers an allergic reaction. If you — or someone you know — comes into contact with gympie gympie, then you should keep an eye out for signs of anaphylaxis, including: 

  • Difficulty breathing
  • A swollen tongue or throat
  • Dizziness
  • Abdominal pain
  • Vomiting 

For treatment, you could try to remove the needles using plaster, warm wax, or even tape. However, experts aren’t sure that it will make any difference — the neurotoxin will still be in your body even if you manage to get the needles out. You also definitely shouldn’t rub or itch the area too much or you’ll make your symptoms worse. 

A general gympie gympie treatment is to take pain medicines — like over-the-counter anti-inflammatories — to help manage your symptoms. You can also try applying various soothing creams to the affected area. Ask your doctor for the best brand recommendations. Eventually, symptoms should clear up on their own.

If you are in gympie gympie’s native habitat and see a plant that even vaguely resembles it, your safest option is to steer clear. Australia contains multiple species of stinging plants, but gympie gympie comes from a particularly dangerous family. A lot of the plants that look like gympie gympie could be just as dangerous to touch. 

There are some safe shrub-like plants in Australia that also have heart-shaped leaves and small flowers. One example is Bossiaea distichoclada. This species only grows up to about three feet tall, though, and has yellow flowers, not white ones. 

Although most Australians are familiar with gympie gympie, plenty of tourists have never heard of it. To be on the safe side, before traveling to any new location, you should always look into the area’s native plants and animals.