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Caution

Oak processionary caterpillars and dogs: what to do

Caution. The hairs of oak processionary caterpillars and their nests can cause blistering, tongue and eye irritation, and sometimes breathing trouble.

If your dog ate or touched this, call your vet or a pet poison line now

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Oak processionary caterpillars and dogs: key facts

Verdict
Caution · Call your vet or a poison line
What it can do
Itchy rash or blisters, tongue irritation, eye irritation, throat irritation and breathing difficulties (occasionally).
What to do now
Call your vet or a pet poison line now. All steps
Sources
GOV.UK (Forestry Commission), Buckinghamshire Council. Reviewed 9 October 2026.

What to do now

  1. Call your vet or a pet poison line now.
  2. Move your dog away from the caterpillars and nests.
  3. Go to a vet right away if your dog has trouble breathing.

Don't

  • Don't touch the caterpillars, hairs or nests, or try to remove nests yourself.

Symptoms to watch for

  • Itchy rash or blisters
  • Tongue irritation
  • Eye irritation
  • Throat irritation
  • Breathing difficulties (occasionally)

Why

The caterpillars are covered in long hairs containing irritating proteins, and their nests hold the hairs too. They live on oak trees in parts of England.

Sources

Guide reviewed 9 October 2026. Page updated 7 November 2026.

General information from the sources above, not a diagnosis. When in doubt, call your vet.