Yeast needs warmth and moisture to ferment, and a stomach supplies both generously. Once swallowed, the dough continues to expand, which can distend the stomach enough to cause pain, retching, and breathing difficulty. Meanwhile fermentation turns sugars into carbon dioxide and ethanol. Animals absorb that alcohol quickly, and a cat's small body means even a modest amount of dough can produce a significant blood alcohol level, leading to wobbliness, disorientation, depression of the nervous system, and in severe cases coma or seizures.
Baked bread does not carry these risks — the yeast is dead and the alcohol has evaporated — though bread is empty calories for a cat and no substitute for cat food. The dangerous window is the countertop rise: bowls of proofing dough should sit somewhere a counter-surfing cat cannot reach.
Sources
- Bread Dough Toxicosis in Animals — Merck Veterinary Manual
- People Foods to Avoid Feeding Your Pets — ASPCA Animal Poison Control
This page is informational and is not veterinary advice. If your pet has eaten something risky, contact your vet or an animal poison control line right away.