brownies, baking supplies (e.g. chocolate chips, cocoa powder), and cocoa bean mulches. Not surprisingly, most accidental chocolate exposures in pets occur around holidays, especially Valentine’s Day, Easter, Halloween and Christmas, when chocolate is more prevalent in the household. Cocoa bean hull mulches are attractive to many dogs and may be ingested as dogs dig through them.

Theobromine

Theobromine is a methylxanthine, in the same class of compounds as caffeine and theophylline. All of these methylxanthines occur naturally in many plants found throughout the world including the cocoa, tea and coffee plants. Theobromine is found primarily in cocoa beans, caffeine in coffee and tea, and theophylline in tea.

Since theobromine occurs naturally in cocoa beans, it is present in all chocolate products. The amount of theobromine in the finished product depends on the type of chocolate and the serving size. Milk chocolate contains less theobromine than semi-sweet or dark chocolate.

Unlike caffeine, theobromine does not stimulate the central nervous system. But it can have a mild diuretic action (increases urine production) similar to caffeine.

Dogs metabolize theobromine very slowly. As a result, theobromine can have a serious effect on the animal's heart, kidneys and central nervous system. It carries the same risk as does a dog's consumption of other common household items such as coffee, tea, cola beverages and certain houseplants.

Theobromine Content Of Products

Source	Serving	Theobromine 1
HERSHEY'S Confectionery products
HERSHEY'S BITES Candies	18 Pieces (39g)	14-57mg
HERSHEY'S COOKIES 'N' CRÉME Candy Bar	1.55 oz (43g)	20mg
KIT KAT Wafer Bar	1.5 oz (42g)	39mg
KRACKEL Chocolate Bar	1.45 oz (41g)	60mg
HERSHEY'S KISSES Brand Chocolate	9 pieces (41g)	74mg
HERSHEY'S Milk Chocolate Bar	1.55 oz (43g)	74mg
HERSHEY'S Chocolate Bar with Almonds	1.45 oz (41g)	61mg
MR. GOODBAR Chocolate Bar	1.75 oz (49g)	58mg
REESE'S Peanut Butter Cups	1.6 oz (45g)	30mg
REESE'S PIECES Candy	1.63 oz (46g)	0mg
ROLO Caramels in Milk Chocolate	7 pieces (42g)	25mg
SKOR Toffee Bar	1.4 oz (39g)	22mg
HERSHEY'S SPECIAL DARK Chocolate Bar	1.45 oz (41g)	184mg
TASTETATIONS Candy	3 pieces (16g)	14mg
HERSHEY'S grocery products
HERSHEY'S Chocolate Syrup	2 Tbsp (39g)	70mg
HERSHEY'S WHOPPERS Chocolate Malt Syrup	2 Tbsp (39g)	47mg
HERSHEY'S Lite Syrup	2 Tbsp (39g)	61mg
HERSHEY'S CHOCOLATE SHOPPE Topping	2 Tbsp (37g)	45mg
HERSHEY'S Chocolate Milk	1 cup (240ml)	36-45mg
HERSHEY'S Cocoa	1 Tbsp (5g)	108mg
HERSHEY'S GOODNIGHT HUGS Hot Cocoa Mixes	1 envelope (25g)	19mg
HERSHEY'S GOODNIGHT KISSES Hot Cocoa Mixes	1 envelope (25g)	37mg
HERSHEY'S HOT COCOA COLLECTION Hot Cocoa Mix	1 envelope	9-82mg
HERSHEY'S Semi-Sweet Baking Chocolate	1 Tbsp (15g)	58mg
HERSHEY'S Unsweetened Baking Chocolate	1/2 bar (14g)	161mg

References 1
The amount of theobromine varies due to growing conditions and cocoa bean variety. Hershey's flavors and quality are maintained with cocoa beans purchased from various cocoa producing countries.

Susceptibility and Clinical Signs

Clinical signs usually occur within 6 to12 hours of ingestion.

• Initial signs include drinking large volumes of water, vomiting, diarrhea, bloating, and restlessness.
• Signs progress to hyperactivity, urinating large volumes, staggering, tremors, and seizures.
• Because of the high fat content of many chocolate products, pancreatitis is a potential sequela 24 to 72 hours after ingestion.
• Death is generally due to cardiac arrhythmias or respiratory failure.

Toxic Doses Based on ASPCA Animal Poison Control Center (APCC) experience: (ASPCA/APCC Database: Unpublished data).

• Mild signs occur in animals ingesting 20 mg/kg of theobromine and caffeine
• Severe signs are seen at 40-50 mg/kg
• Seizures occur at 60 mg/kg 
• Death 100mg/kg

Using a dose of 100 mg/kg as the toxic dose it comes out roughly as:
1 ounce per 1 pound of body weight for Milk chocolate
1 ounce per 3 pounds of body weight for Semisweet chocolate
1 ounce per 9 pounds of body weight for Baker's chocolate.

So, for example, 2 oz. of Baker's chocolate can cause great risk to an 15 lb. dog. Yet, 2 oz. of Milk chocolate usually will only cause digestive problems.

Treatment
There is no specific antidote for this poisoning. And the half life of the toxin is 17.5 hours in dogs.

• Induce vomiting in the first 1-2 hours if the quantity is unknown.
• Administering activated charcoal may inhibit absorption of the toxin.
• An anticonvulsant might be indicated if neurological signs are present and needs to be controlled.
• Oxygen therapy, intravenous medications, and fluids might be needed to protect the heart.
• Milk chocolate will often cause diarrhea 12-24 hours after ingestion. This should be treated symptomatically (fluids, etc..) to prevent dehydration.

Parts of this article adapted from research by Sharon Gwaltney-Brant, DVM, PhD