Suspect poisoning? US: ASPCA Poison Control (888) 426-4435 · UK: 01202 509 000 · Severe symptoms → nearest emergency vet now.

How much moldy bread is dangerous for a cat?

Cats · Emergency guide

Last reviewed: 2026-09-05 · Reference ranges: ASPCA, Pet Poison Helpline & Merck Veterinary Manual

Short answer

Any amount of moldy food is dangerous for cats. The tremorgenic mycotoxins in mold can cause severe neurological signs like whole-body tremors, vomiting, and high fever within hours. Even a small bite can be toxic due to the concentration of these compounds. Call the ASPCA poison line (888-426-4435) immediately if your cat has eaten moldy food, and watch for tremors or wobbliness.

Why is this dangerous?

Mould growing on bread, pasta, nuts, cheese and garden compost can produce tremorgenic mycotoxins (penitrem A, roquefortine). These over-stimulate the nervous system and cause whole-body tremors, rigidity and high body temperature within 30 minutes to a few hours.

The same mouldy food can also carry aflatoxins, which damage the liver over the following days. Compost is a double risk because it ferments and can also contain alcohol.

Why speed matters

Delaying care significantly worsens outcomes. Some signs appear hours or days later, so "looks fine right now" is not a reason to wait.

Signs to watch for

  • Sudden whole-body tremors, shivering, muscle rigidity
  • Wobbliness, unable to stand or walk
  • Vomiting, drooling, restlessness, panting
  • High body temperature from muscle activity
  • Seizures, collapse, coma in severe cases

What to do right now

  1. Call your vet or a poison line and go in — tremors are exhausting and raise body temperature dangerously.
  2. Keep the pet cool with a fan and cool damp towels; do not use ice-cold water.
  3. Do not induce vomiting if the pet is already trembling or unsteady.
  4. Secure bins and compost with pet-proof lids; never compost in an open heap a pet can reach.
If your pet shows any of the signs above, go to the nearest emergency vet now and call ahead.

The step-by-step response, from the first minute to the vet visit, is in our Moldy Food, Compost & Bin Raids emergency guide.

Open the full emergency guide: Moldy Food, Compost & Bin Raids →