Give chocolate to loved ones, and you could end up poisoning them. That is, if the loved ones are your pets.

Even small amounts of theobromine, an ingredient in chocolate, can cause vomiting and restlessness in pets. Larger doses can be fatal. While most pet owners expect a dog to develop an upset stomach after eating a large amount of chocolate, few realize its toxic potential.

The lethal dose of theobromine depends on the size of the dog and the type of chocolate. Ounce for ounce, baking chocolate has six to nine times as much of the substance as milk chocolate does.

Estimates of the smallest amounts that can be fatal are:

• 4 to 10 ounces of milk chocolate or 1/2 to 1 ounce of baking chocolate for small dogs, such as Chihuahuas and toy poodles.
• 1 to 1 1/2 pounds of milk chocolate or 2 to 3 ounces of baking chocolate for medium-sized dogs, like cocker spaniels and dachshunds.
• 2 to 4 1/2 pounds of milk chocolate or 4 to 8 ounces of baking chocolate for large dogs, including collies and Labrador retrievers.

Cats have much different eating habits and seldom are poisoned by chocolate.

While a very small amount of chocolate may not harm some dogs, it’s safest to avoid giving it to them at all. If an accident occurs, a veterinarian should be consulted. Treatment may require inducing vomiting, stabilizing the animal’s heartbeat and respiration, controlling seizures and slowing the absorption of theobromine. If the animal already is comatose, its stomach may need to be pumped.