Is Stinging Nettle toxic to dogs?

Fine hairs called trichomes break upon contact, injecting histamine and other irritants into the skin or oral tissues, causing localized inflammation or systemic toxicity if ingested.

For hives, vets usually give an antihistamine, often with a steroid, and may prescribe an antihistamine by mouth for 3 to 5 days to stop them coming back. A severe allergic reaction (anaphylaxis) is treated as an emergency with epinephrine (adrenaline), fluids and other supportive care. In a 2019 report, two gun dogs with severe signs had hospital care, including IV fluids, antihistamines, stomach-protecting drugs, pain relief, antibiotics and steroid eye drops.

Most stings cause local irritation that clears on its own within minutes to a few hours. Hives from any cause often fade within a few hours, though mild cases can take 12 to 48 hours. Hives rarely kill a dog; the danger is anaphylaxis or swelling of the airway. In a 2019 report, two gun dogs with nerve and muscle signs after suspected nettle exposure recovered fully with hospital care, although one of them reacted three times in three weeks.

• Stinging nettle (Urtica dioica), also called tall or wild nettle, grows on damp ground: stream and river banks, flood plains, ditches, meadows, woodland clearings and disturbed ground. It often forms thick patches.
• Woodland, fields and undergrowth on walks, runs and hunts. Short-coated dogs and hunting dogs that push through cover meet it most often.
• Gardens and yards, where it spreads and can form dense patches.
• The stinging hairs on its leaves and stems. Their brittle tips snap off when touched and inject an irritating fluid, so just brushing past can sting the skin, nose or face. Chewing the plant pushes the hairs into the mouth.

• Learn to recognise it: a tall, upright plant with square stems and pairs of egg-shaped, saw-toothed leaves covered in fine stinging hairs. It often grows in thick patches.
• Keep your dog on the path or on a lead in damp woodland, marshy ground, stream banks and ditches where nettles grow thickly. Take extra care with short-coated and hunting dogs that run through undergrowth.
• Keep pets away from nettle in your own garden. It spreads through underground stems and seed and can form dense patches.
• After a reaction, avoid that patch, because reactions can come back with repeated contact. Many animals learn to avoid nettles once stung, but don't count on it: one dog in a case report reacted three times in three weeks.