Theobromine, a methylxanthine found in cacao seeds, can cause toxicosis when ingested by pets. Dogs are the most frequently intoxicated species due to their indiscriminate eating habits. Any age or breed of dog can be affected. A similar clinical course can also occur in cats and birds if ingestion occurs.

Baker’s chocolate and dry cocoa powders have higher methylxanthine content and are considered more dangerous than milk chocolate. White chocolate, on the other hand, contains very low levels of methylxanthine.

Chocolate

It is important to note that chocolate products often contain both theobromine and caffeine (another common pet toxin).

Cacao bean shells are frequently used in mulch products, causing toxicosis not only in dogs and cats but also pigs, calves, chickens, ducks and horses.

Signs and symptoms of toxicity: vomiting, diarrhea, panting, excessive thirst and urination, abnormal heart rhythm, tremors, seizures. These signs usually occur within 2-4 hours of ingestion.

Toxic Consumption:
In dogs, 250 mg/kg (113 mg/lb) can be toxic. For cats that drops slightly to 200 mg/kg (90 mg/lb).

 

Dogs: Theobromine Toxic Consumption
X-Small
Yorkie, Chihuahua
Small
Pug, Boston Terrier, Poodle
Medium
Beagle, Scottish Terrier
Large
Boxer, Cocker Spaniel
X-Large
Retriever, German Shepherd
XX-Large
Great Dane, St. Bernard
1 – 10 lbs.
(0.45 – 4.6 kg)
11 – 25 lbs.
(5 – 11.4 kg)
26 – 40 lbs.
(11.8 – 18.2 kg)
41 – 70 lbs.
(18.6 – 31.8 kg)
71 – 90 lbs.
(32.3 – 40.9 kg)
91 – 110 lbs.
(41.4 – 50 kg)
dog1 dog2 dog3 dog4 dog7 dog6
Cacao Beans > 0.075 oz > 0.8 oz > 1.5 oz > 3 oz > 5 oz > 6.5 oz
Unsweetened Baking Chocolate > 0.2 oz > 2.5 oz > 6.5 oz > 10 oz > 17.5 oz > 22.5 oz
Dark Chocolate > 0.5 oz > 9 oz > 21.5 oz > 34 oz > 59.5 oz > 76.5 oz
Milk Chocolate > 1.5 oz > 20.5 oz > 49 oz > 77 oz > 134.5 oz > 172 oz
White Chocolate > 450 oz > 5000 oz > 11800 oz > 18600 oz > 32300 oz > 41400 oz
Cocoa Powder > 0.15 oz > 1.5 oz > 4 oz > 6 oz > 10.5 oz > 14 oz
Cocoa Bean Mulch > 0.125 oz > 1 oz > 3 oz > 5 oz > 8.5 oz > 11 oz

 

Cats: Theobromine Toxic Consumption
Most Cats

Large Cats
1 – 10 lbs.
(0.45 – 4.6 kg)
11 – 25 lbs.
(5 – 11.4 kg)
cat1 fat cat
Cacao Beans > 0.05 oz > 0.5 oz
Unsweetened Baking Chocolate > 0.2 oz > 2 oz
Dark Chocolate > 0.5 oz > 7 oz
Milk Chocolate > 1.5 oz > 16.5 oz
White Chocolate > 360 oz > 4000 oz
Cocoa Powder > 0.1 oz > 1 oz
Cocoa Bean Mulch > 0.1 oz > 1 oz

References:
– Osweiler, G, et al. (2011). Blackwell’s five-minute veterinary consult clinical companion. Small Animal Toxicology. [Kindle version]. Retrieved from Amazon.com
– The Merck Veterinary Manual. Chocolate. Available at: http://www.merckmanuals.com/vet/toxicology/food_hazards/chocolate.html?qt=chocolate&alt=sh. Accessed August 31, 2014.