Chocolate contains theobromine, which is a stimulant that can be toxic to cats. However, the amount of theobromine in chocolate varies depending on the type of chocolate. Dark chocolate contains the highest amount of theobromine, followed by semisweet chocolate, and then milk chocolate. White chocolate contains very little theobromine.
The toxic dose of theobromine for cats is 100-200 mg/kg of body weight. A 10-pound cat would need to eat about 1 ounce of dark chocolate to reach the toxic dose. However, most cats would not eat that much chocolate at one time.
If your cat does eat chocolate, it is important to monitor them for signs of toxicity, such as vomiting, diarrhea, increased thirst, and urination, panting, and seizures. If you see any of these signs, take your cat to the vet immediately.