Dogs cannot have chocolate because it can cause them to be sick and can even be fatal. Chocolate is one of the main causes of poisoning in dogs. Many people tend to feed dogs chocolate without knowing the dire consequences that they might face; even though some "people foods" are acceptable in moderation, it does not mean that every food should be shared with pets.
It is critical to note that there is no recommended amount of chocolate to give to a dog. White and milk chocolate do not pose as big a risk to a dog as dark chocolate. Chocolate is made from cocoa beans which contain caffeine and a chemical compound called theobromine. This chemical compound is really dangerous when consumed by a dog.
The rate of metabolizing theobromine in dogs is lower than in humans. It may take hours for theobromine to be metabolized in dogs when it only takes 20 to 40 minutes in humans. Dogs are known to consume just about anything, making them vulnerable to poisoning. Small amounts of chocolate can cause dogs to have diarrhea and vomit. Excessive consumption of chocolate can lead to high blood pressure, tremors, respiratory failure, increased heart rate, cardiac arrest, seizures and hyperactivity.