Chocolate is a Poison to Dogs

(Source: Dog Topics)

What makes chocolate toxic, anyway?
Chocolate is made from the fruit (beans) of the cacao tree. Theobromine, a component of chocolate, is the toxic compound in chocolate. It is a naturally occurring stimulant found in the cocoa bean, theobromine increases urination and affects the central nervous system as well as heart muscle. While amounts vary by type of chocolate, it's the theobromine that is poisonous to dogs. (Caffeine is also present in chocolate, but in much smaller amounts than Theobromine.) Both Theobromine and Caffeine are members of a drug class called Methylxanines.

Theobromine and caffeine effects on the body:

Central Nervous System (CNS) stimulant
Cardiovascular stimulant
Increase blood pressure (mild)
Nausea and vomiting
Are some chocolates more toxic than others?
Yes. Unsweetened (baker's) chocolate contains 8-10 times the amount of Theobromine as milk chocolate. Semi-sweet chocolate falls roughly in between the two for Theobromine content. White chocolate contains Theobromine, but in such small amounts that Theobromine poisoning is unlikely. Caffeine is present in chocolate, but less than Theobromine.


Why isn't chocolate toxic to humans?
Humans can break down and excrete Theobromine much more efficiently than dogs. The half life of Theobromine in the dog is long; approximately 17.5 hours.

How Much Chocolate Is Deadly?

White chocolate: 200 ounces per pound of body weight. It takes 250 pounds of white chocolate to cause signs of poisoning in a 20-pound dog, 125 pounds for a 10-pound dog.

Milk chocolate: 1 ounce per pound of body weight. Approximately one pound of milk chocolate is poisonous to a 20-pound dog; one-half pound for a 10-pound dog. The average chocolate bar contains 2 to 3 ounces of milk chocolate. It would take 2-3 candy bars to poison a 10 pound dog. Semi-sweet chocolate has a similar toxic level.

Sweet cocoa: 0.3 ounces per pound of body weight. One-third of a pound of sweet cocoa is toxic to a 20-pound dog; 1/6 pound for a 10-pound dog.

Baking chocolate: 0.1 ounce per pound body weight. Two one-ounce squares of bakers' chocolate is toxic to a 20-pound dog; one ounce for a 10-pound dog.

(Source: About.com & Dog Owner's Digest)
(Suggested by Alex Swee)
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