The toxic dose of theobromine is about 100mg to 150mg per kg body weight of the dog.
Milk chocolate contains 6mg per ounce and baking chocolate contains 35mg – 45mg per ounce. Milk chocolate carries a smaller threat whilst other types of chocolate can pose a bigger problem.
White chocolate – not a big problem (though may still cause an upset tummy)
Milk Chocolate – will need treatment if eaten more than 9 grams of chocolate per kilo bodyweight.
Plain Chocolate – Will need treatment if eaten more than 1 gram per kilo bodyweight.
Cocoa powder/Dark Chocolate – Will need treatment if eaten more than 0.7grams per kilo bodyweight.
Affecting the nervous system, heart rate and peripheral nerves. It also has a diuretic effect. Dogs are hyperexciteable. Nervous excitement progressing to fits and coma. Panting. Tachycardia (abnormally rapid heartbeat). Restless, increased urination, vomiting and muscular tremors. Can sometimes lead to hypothermia or in severe cases cardiac arrest. Death can result from severe intoxication.
Induce vomiting (within one-two hours of ingestion), gastric lavage may be required. Prepare activated charcoal solution may need to be administered by a vet. Fitting treatment may be given such as phenobarbitone or diazepam.
A secondary problem then results in probable diarrhoea, which would require 24 hour starving then light meals of chicken or fish.
Veterinary Advice should be sought if excessive quantities have been ingested, if in doubt always seek the advice of a vet.