I know I shouldn't feed a cat chocolate, and I also know dogs can get sick from it. Do I have to worry for my cat's health if (s)he eats some chocolate?
I would keep chocolate well away from any cat or dog.
- Xanthines (a class of alkaloids which I believe includes caffeine as well as theobromine (present in cocoa)) have very low toxicity to humans but this is not true for cats or dogs.
- Alkaloids (in general) are designed to both deter herbivores with their bitter flavor, and kill them if they don't get the hint (strychnine and many other alkaloids are quite toxic to most animals).
I would freak out if my cat ate chocolate (or for that matter: onions, garlic, mushrooms, broccoli - those all have other phytotoxins in them). Certainly, there are cats and dogs have lived after eating chocolate, but likely they got some organ damage as a result of it, and plenty have also died from it.
Theobromine poisoning: cats, dogs & humans (humans can take much higher doses even mg/kg of theobromine because we have defenses like cytochrome P450 (http://en.wikipedia.org/wiki/Cytochrome_P450)) http://en.wikipedia.org/wiki/Theobromine_poisoning
Chocolate contains potential toxins for cats: theobromine and caffeine. Animals are unable to process these in large amounts. Human beings can eat chocolate with varying success, as we are larger and able to process the theobromine in relatively small quantities. What would be a small quantity for a person (in terms of grams / body weight) may be a large quantity for a cat.
It cannot be definitively answered whether your cat has been, effectively, poisoned by an ingestion of chocolate. The best thing would be to monitor your pet for any symptoms of toxicity and do not delay seeking veterinary treatment. A cat will usually display signs of toxicity with the first few hours of ingesting the chocolate, but this can be delayed for up to 12 hours.
Some signs to look out for:
- vomiting and/or diarrhoea
- trembling, seizure
- hyperactivity, both behaviourally and physiologically, increased heart rate
- any changes or signs of unwellness
Always, if in doubt, the internet is no substitute for professional veterinary attention, which a consultation with your local vet can provide.