Why?
In the warmth of the stomach, the yeast keeps working: the dough expands, can stretch the stomach and cause severe pain. Fermentation also produces ethanol, which is absorbed into the bloodstream and causes alcohol poisoning. Doughs without yeast, like cookie or pie dough, don't rise, but they still contain raw flour, often raw egg and sugar, and sometimes chocolate.
How much?
No amount is safe. Let dough rise covered, out of reach, in a room your cat can't get into, and don't let them lick the bowl or utensils.
The risks
- Swollen, painful belly; trying to vomit without success
- Wobbly walking, disorientation, lethargy
- Low body temperature and low blood sugar
- Seizures in severe cases
- Raw flour and eggs: bacteria such as E. coli or salmonella
Your cat ate some: what now?
Call your vet or an emergency clinic right away, even if your cat seems fine: signs can appear within a few hours. Don't try to make your cat vomit yourself; home methods are dangerous for cats, and that decision belongs to the vet. Note the time and roughly how much was eaten.
Better options
If your cat hangs around the kitchen while you bake, keep them busy with a cat treat or a toy. Once baked, a tiny piece of plain bread isn't dangerous.
Common questions
What about raw cookie dough?
It doesn't rise like yeast dough, but it contains raw flour and eggs, sugar, butter and often chocolate. Call your vet for advice, especially if there was chocolate in it.
Is baked bread dangerous too?
No. Baking kills the yeast, so bread no longer ferments. A small piece of plain bread isn't dangerous, even if it doesn't do your cat any good.
This information is general and does not replace advice from a veterinarian. If your cat has swallowed something toxic, call your vet or an animal poison control center right away, without waiting for symptoms.