We realized our kitten got a coffee bean quite a while ago and it's not exhibiting any weird symptoms that we can realize. Should we worry?
Contact your vet.
Caffeine is indeed toxic to cats. According to vetmeds.org, cats can only tolerate about 36 to 68 milligrams per pound. For a small cat, they estimate that amounts to less than .05 ounces of coffee beans, which is a very tiny amount. If your kitten is very small, the risk is even greater. So perhaps if the kitten has truly only eaten one bean, it may not need medical attention, but I would definitely at minimum consult your vet as soon as possible.
As stated on pet poison helpline, symptoms of caffeine poisoning may include:
- Elevated heart rate
- Elevated blood pressure (hypertension)
- Elevated body temperature (hypothermia* [sic])
- Abnormal heart rhythm
*Original source says "hypothermia" and this was preserved in quotation, but the actual correct word in this context is "hyperthermia".
This should be harmless, based on gathering the numbers in the other answer and the comments therein.
A dangerous dose for a cat is around 36 to 68 mg of caffeine per pound (79 to 150 mg per kg) of cat weight. A single coffee bean is around 0.13g and contains between 1 to 10 mg of caffeine. Additionally, your cat swallowed an entire bean, not the same amount of finely ground coffee. It can't digest it, so most of the caffeine will just pass through your cat unaltered. You said she is not showing any symptoms so I wouldn't worry about it.