Chocolate contains theobromine and caffeine which are both toxic to dogs and cats. Chocolate toxicity is dependent on the type of chocolate, the amount ingested and the size of your pet. Due to their indiscriminate eating habits, dogs are far more likely to ingest a toxic amount of chocolate than cats. Symptoms of chocolate poisoning in dogs include restlessness, excitement, hyperactivity, nervousness, trembling, vomiting, diarrhoea, increased drinking and urination, increased heart rate and seizures. Darker chocolate is more dangerous than milk chocolate. White chocolate has minimal levels of methylxanthines, while baking chocolate contains the highest amounts. Chocolate poisoning in dogs can be life threatening so always call the Animal Poisons Centre or a vet if you suspect your dog has ingested any.