Dogs and some cats find chocolate very tasty - but too much can be fatal - so "Keep chocolate out of the reach of dogs and cats"

Just like us, dogs and some cats find chocolate highly palatable but it is important to avoid giving too much. There are some minor problems that can result from too much chocolate :

• Chocolate is high in calories so it can contribute to the development of  obesity
• Dogs fed chocolate regularly are predisposed to develop tooth decay (caries) because of the high sugar content
• Too much chocolate can reduce the animals appetite for it's normal ration
• Chocolate contains the chemical theobromine - which is toxic, and potentially lethal to dogs and cats. One reason for this is that dogs are unable to clear theobromine from their bodies as quickly as humans can. 

The signs of chocolate poisoning due to the theobromine toxicity include :

• Increased urine production (diuresis)

• Diarrhoea

• Vomiting

• Lethargy

• Depression

• Muscle tremors

• Death

The official LD₅₀ (a measure of the toxicity of a product) of theobromine in dogs is 240-500 mg/kg body weight of the animal. But there is a report of a dog dying after eating only 114 mg/kg body weight. 

Milk chocolate contains about 1.5mg theobromine per gram, and unsweetened baking chocolate contains upto 15mg per gram. So potentially toxic levels can be reached in a 10kg dog by eating only 2.2oz (63grams) of unsweetened cooking chocolate, or  23.5 oz (1.5lb or 670 grams) of milk chocolate. 

Updated January 2016