Why can’t dogs eat chocolate?

Dogs will be poisoned by foods containing theobromine. Chocolate is processed from cocoa beans and contains a variety of methylxanthine derivatives. Caffeine and Theobromine belongs to this type of substance. These substances bind to certain receptors on the cell surface, thereby preventing natural substances in the animal's body from binding to the receptors. After dogs eat it, it will cause a burden on the heart and cause poisoning, such as vomiting and diarrhea, frequent urination, hyperactivity, accelerated heartbeat and breathing, and even death due to loss of cardiovascular function. Data shows that a dog weighing 1 kilogram may die if it eats 9 grams of pure chocolate.

Why are humans not poisoned by theobromine?

This is because we humans metabolize theobromine very quickly. After people eat chocolate, our bodies can quickly detoxify the toxic theobromine through the liver and convert it into non-toxic substances, which are then excreted out of the body through the kidneys.
Dogs do not metabolize theobromine so quickly. It takes about 20 hours for a dog to eliminate half of the theobromine in its body. Therefore, the toxic theobromine will accumulate in the dog’s body and cause damage to it.