Adder Bites (UK and Europe)
Most UK dogs bitten by an adder recover, but about 1 in 20 in poison-service records died. The signs, what to do on the way to the vet, and what doesn't help.
Written by thecanineledger
If you think an adder has bitten your dog: phone your vet and go now, even if your dog seems fine. Keep your dog as calm and still as you can, and carry it if it’s small enough. Don’t give any medicine at home unless your vet tells you to.
Our note: “Carry it” and “keep it still” are standard first-aid advice. None of the sources we read gives first-aid steps.
Adder bites are rarely fatal, but they’re far from harmless. In a study of dogs reported to the UK’s Veterinary Poisons Information Service (VPIS) between 1985 and 2010, “97 per cent of dogs were symptomatic”, and “mortality is low (4.6 per cent died)” (Sutton et al., Veterinary Record 2011, abstract). A newer analysis of VPIS cases from 2011 to 2024 found a similar figure: 23 of 467 dogs with a usable outcome record, or 4.9%, died (Ainsworth et al., preprint 2026, abstract).
While those odds favour your dog, a bite can cause serious complications, and you can’t tell at home which dogs will need treatment. This page explains the signs, what happens at the vet, and what doesn’t help.
1. Where and when bites happen
The European adder, Vipera berus, bites dogs in the UK and across Europe, with case studies from Sweden and Germany among others. A Swedish study calls it “the only venomous viper in Sweden” (Lervik et al., Acta Veterinaria Scandinavica 2010).
Spring and early summer. In the UK study, “Most bites (69.2 per cent) occurred between April and July”, especially in the afternoon. Bites were reported most often in south-east England.
Usually the face. In the Swedish study, 77% of dogs were bitten on the head or nose. Most others were bitten on a leg.
Our note: This page covers the European adder only. Southern Europe has other vipers.
2. The signs
Swelling. In the Swedish study, every dog had swelling at the bite. The newer UK analysis found swelling in 77.1% of dogs.
A quiet, flat dog. In Sweden, “73 per cent had affected mental status”, meaning they were dull or depressed. The UK study lists “lethargy, depression, hyperthermia and tachycardia”. Hyperthermia is a high temperature; tachycardia is a fast heart rate.
Signs come on fast. “Initial clinical effects usually occurred within two hours” in the UK study.
Signs can be delayed or hidden. About a third of UK dogs had only local effects, but two-thirds had effects on the whole body as well. The newer analysis lists complications including blood-clotting problems, tissue death, heart and circulation problems, and kidney damage. Four dogs needed surgery, two of them a leg amputation.
You may not see the snake. The newer analysis found “diagnostic uncertainty” was one of the commonest problems vets reported.
3. At the vet
Monitoring. Because of the complications above, your vet may keep your dog in to watch its heart, blood clotting and kidneys.
Antivenom. In the UK study, antivenom was used in 55.9% of dogs and “appeared to significantly reduce duration of oedema from an average of 94 to 47 hours”. Oedema is swelling. The newer analysis found vets reported problems with “antivenom access or affordability”.
Recovery. The UK study found “full recovery typically occurring five days after the bite”. In Sweden, swelling had gone in every dog checked between 9 and 23 days after the bite.
Our note: The 2026 analysis is a preprint and not yet peer-reviewed. We use it alongside the 2011 study because it is more recent.
4. What doesn’t help: a routine steroid jab
Steroids have long been given to dogs after adder bites. A Swedish randomised, double-blind trial tested this in 75 dogs. A single steroid injection “did not affect clinical or clinicopathological parameters” (Brandeker et al., BMC Veterinary Research 2015). Clinicopathological means blood-test results.
What it means for you. Don’t give your dog any medicine at home, including antihistamines or steroids you have in the house, unless your vet tells you to. Drive to the vet instead.
Our note: The trial tested one steroid, given once as an injection. It didn’t test antihistamines.
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5. What we could not verify
| Commonly said | What we found |
|---|---|
| “Adder bites usually kill dogs” | No. About 1 in 20 dogs in UK poison-service records died. |
| “If the dog seems fine, it’s fine” | Not safe to assume. Nearly all bitten dogs developed signs, usually within two hours. |
| “Give an antihistamine straight away” | We found no evidence for it. See your vet instead. |
| “Steroids help” | Not as a routine single injection. A Swedish trial found no effect. |
| “Antivenom is always given” | No. It was used in just over half of UK cases, and vets report access problems. |
Sources
- Sutton NM, Bates N, Campbell A. Canine adder bites in the UK: a retrospective study of cases reported to the Veterinary Poisons Information Service. Vet Rec 2011. ⚠️ abstract read. Retrospective case series, 1985–2010
- Ainsworth S, Bates N, Edwards JN. Adder envenoming in dogs and cats: morbidity, fatal outcomes and management challenges. Research Square preprint 2026. ⚠️ not peer-reviewed; abstract read. 1,229 dog enquiries, 2011–2024
- Lervik JB, Lilliehöök I, Frendin JH. Clinical and biochemical changes in 53 Swedish dogs bitten by the European adder: Vipera berus. Acta Vet Scand 2010: prospective case series
- Brandeker E, Hillström A, Hanås S, et al. The effect of a single dose of [drug name omitted] in dogs envenomated by Vipera berus: a randomized, double-blind, placebo-controlled clinical trial. BMC Vet Res 2015: randomised controlled trial, 75 dogs. The drug’s name is omitted from the title here
Always confirm with your vet before acting on anything on this page.