What does an adder bite look like on a dog?

Painful swelling around the bite — often on the face, legs, or nose — develops within hours. Two small puncture marks may be visible. The dog may yelp, limp, or become lethargic.

Is an adder bite an emergency for dogs?

Yes — all suspected adder bites need urgent veterinary care. Swelling can affect breathing if the face is bitten. Small dogs and puppies are at higher risk of serious reactions.

What should I do if my dog is bitten by an adder?

Keep your dog calm and still, carry small dogs if possible, do not apply a tourniquet or try to suck venom, and go to your nearest vet immediately. Call ahead if you can.

Where are adders found in the UK?

Adders live on heathland, moorland, woodland edges, and sand dunes — mainly England, Wales, and Scotland. They are shy and bite when disturbed, often when dogs explore undergrowth.

Reptile Health

Adder Snake Bites in Dogs UK — Signs, First Aid & When to Call a Vet

Published 25 June 2026Last updated 25 June 20263 min read

Quick answer

The adder is the UK's only venomous snake. Bites cause painful swelling — often on the face or leg after dogs disturb basking snakes on heaths and woodland. Go to a vet immediately — keep your dog still; do not suck the wound or use ice packs without vet advice.

What is an adder?

The European adder (Vipera berus) is the only venomous snake native to Britain. Adders are shy and usually bite only when stepped on or investigated by curious dogs.

They are found on:

Heathland and moorland
Woodland edges and sandy dunes
Rough grassland in spring and summer

Adders are legally protected in the UK — do not attempt to kill or capture the snake.

How adder bites happen

Most UK dog bites occur when dogs:

Sniff under heather, bracken, or logs
Chase movement in long grass
Put their nose into a basking adder's path

Bites are most common March to October when adders are active.

Symptoms of adder envenomation

Signs usually develop within minutes to a few hours:

Sign	Notes
Sudden yelp or limping	At moment of bite
Painful swelling	Rapidly enlarging around bite site
Bruising and redness	Spreads from puncture marks
Lethargy & vomiting	Systemic effects
Pale gums, weakness	Severe envenomation
Breathing difficulty	Especially if face or neck bitten

Facial bites are particularly dangerous because swelling can compromise airways.

First aid — what to do

According to the PDSA and Blue Cross:

Keep your dog calm and still — movement spreads venom faster
Carry small dogs — minimise walking
Go to a vet immediately — call your practice or emergency clinic en route
Do not cut the wound, suck venom, or apply a tourniquet
Do not give human painkillers — see ibuprofen poisoning

If you saw the snake, note grey-brown zigzag pattern along the back — helpful for vets but do not delay to identify it.

What your vet will do

Treatment depends on severity:

Pain relief and monitoring
Antihistamines and fluids for swelling and shock
Antivenom — used in some severe UK cases at specialist centres

Most dogs recover with prompt care. Delayed treatment increases complication risk.

Prevention on UK walks

Keep dogs on lead in known adder habitats during warm weather
Stay on paths through heathland and dunes
Train a reliable recall before off-lead access to high-risk areas
Check seasonal pet care for summer countryside risks

Adder vs other bites

Cause	Typical pattern
Adder	Rapid painful swelling after countryside walk
Insect sting	Local swelling — often paw or muzzle; see pet first aid UK
Paw injury	Sudden lameness — see Dog limping causes

Sources & further reading

Facts in this guide are rewritten in plain English from publicly available UK advice. We name the organisation where a specific point comes from their guidance. Links below go to the original pages — use them to read the source material directly.

PETHEALTH+ is independent. These organisations do not sponsor, approve, or partner with this website. Guidance checked against sources listed below (last updated 2026-06-25).

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Frequently Asked Questions

What does an adder bite look like on a dog?: Painful swelling around the bite — often on the face, legs, or nose — develops within hours. Two small puncture marks may be visible. The dog may yelp, limp, or become lethargic.
Is an adder bite an emergency for dogs?: Yes — all suspected adder bites need urgent veterinary care. Swelling can affect breathing if the face is bitten. Small dogs and puppies are at higher risk of serious reactions.
What should I do if my dog is bitten by an adder?: Keep your dog calm and still, carry small dogs if possible, do not apply a tourniquet or try to suck venom, and go to your nearest vet immediately. Call ahead if you can.
Where are adders found in the UK?: Adders live on heathland, moorland, woodland edges, and sand dunes — mainly England, Wales, and Scotland. They are shy and bite when disturbed, often when dogs explore undergrowth.