Humans aren’t the only ones with a sweet tooth. Dogs often like the smell of chocolate, making it a tempting treat to taste. However, because dogs cannot digest and eliminate the main toxic components — the methylxanthine alkaloids theobromine and caffeine — as quickly as humans, they experience poisoning when indulging in the sweet stuff. If your dog eats chocolate, regardless if it’s milk or dark, consider it an emergency and call your veterinarian or animal poison control immediately.

If your dog eats chocolate, here’s what to do first

If you suspect your dog ate chocolate, call your veterinarian or the ASPCA Animal Poison Control Center (888-426-4435) immediately. Do not wait for symptoms to emerge before contacting your vet.

Ideally, include the type of chocolate your dog ate, how much and when. Bring the chocolate source, if possible, say veterinarians Kathy Gerken and Kendon Kuo. Both work in small animal emergency and critical care at Auburn University Bailey Small Animal Teaching Hospital in Alabama.

“Collect any remaining packaging from the chocolate to help your veterinarian determine what type of chocolate it was and how much your dog may have ingested,” says Dr. Tina Wismer, senior director of ASPCA Animal Poison Control Center in Urbana, Illinois. “Note whether the chocolates had any sort of fillings, including raisins or macadamia nuts, as they can also be toxic. If the chocolate is sugar-free, it could also contain xylitol, a toxin that can cause low blood sugar and liver damage in our dog friends.”

Symptoms of chocolate toxicity in dogs

Even if you don’t catch your dog eating chocolate, you may see clues something is not right. Initial signs your dog may be experiencing chocolate toxicity may show up in the first couple hours after ingestion, but it can take up to 24 hours, and recovery can take up to three days.

Symptoms of chocolate poisoning in dogs include:

• Vomiting (mild symptom)
• Diarrhea (mild symptom)
• Increased thirst (mild symptom)
• Hyperactivity (mild symptom)

More serious symptoms include:

• Increased or irregular heart rate or rhythm (including panting, lethargy, confusion, dizziness and shortness of breath)
• Muscle tremors
• Seizures

“Severe signs include the previous but affect the central nervous system, as well, leading to seizures, coma and sometimes death,” say Drs. Gerken and Kuo.

Why is chocolate toxic to dogs?

“Chocolate toxicosis is a very common episode and should always be treated as a medical emergency,” say Drs. Gerken and Kuo.

When ingested, methylxanthines affect the dog’s central nervous system, cardiovascular system and respiratory system. Chocolate toxicity symptoms in dogs can range from mild to severe to fatal.

While theobromine occurs naturally in cocoa beans, the amount in chocolates depends on the type of chocolate as well as the brand and size of the candy.

“The darker the chocolate, the more concentrated amounts of methylxanthines are present,” say Drs. Gerken and Kuo.

The darker the chocolate, the more toxic for dogs

Here are the most common types of chocolate, from most dangerous to least toxic, and the approximate amount of methylxanthine per ounce of chocolate.

1. Cocoa powder (~800mg/oz)
2. Unsweetened/Baker’s chocolate (~450mg/oz)
3. Semi-sweet chocolate (~150-160mg/oz)
4. Dark chocolate (~150-160mg/oz)
5. Milk chocolate (~64mg/oz)
6. White chocolate (n/a)

Note: These numbers come from Merck Vet Manual

An easy way to remember is that the more bitter the chocolate tastes, the more toxic it is for dogs. But all of them can have unpleasant effects on our dogs.

“White chocolate is not risk-free but carries a significantly lower dose of toxins and is generally not an issue with regard to methylxanthines,” say Drs. Gerken and Kuo. “However, white chocolate ingestion has a higher association with gastrointestinal upset and pancreatitis.”

Understandably, the most common incidences of dogs eating chocolate happen during holidays, including Easter, Halloween and Christmas. The variety of chocolates that vets treat dogs for eating ranges from candy bars to cookies to chocolate bars and baked items.

“Typically, most chocolate candies contain milk chocolate or white chocolate,” say Drs. Gerken and Kuo. “Dogs tend to consume these in larger amounts making up their toxicity. With baked goods, the chocolate tends to be darker and/or purer cacao, with higher concentrations of the toxins, meaning it takes much less to be ingested to become toxic. Additionally, baked goods may contain other items, such as raisins, macadamia nuts or marijuana that could also pose additional toxicity risk.”

How much chocolate is toxic to dogs?

ASPCA and Merck Vet Manual both say 100 to 200 mg of theobromine and caffeine per kg of dog weight is a lethal dose.

“We start seeing clinical signs around 20 mg/kg and they progressively get worse as they increase,” say Drs. Gerken and Kuo. “But the 100 mg/kg of either substance (theobromine or caffeine) is essentially fatal. For a 15-pound dog that eats 1-ounce of a 72 percent cocoa chocolate bar, that dog would receive about 42 mg/kg of methylxanthines and result in significant cardiac arrhythmias.”

Remember that the dose determines the poison.

“The amount of chocolate that may be toxic to your pet depends on their size and medical history,” says Dr. Wismer. “It takes much less chocolate to be a problem for smaller dogs than larger dogs”

And while age is not a major factor in assessment, your dog’s history is significant.

“If the dog already has a history of gastrointestinal, cardiac and/or neurological disease, there is a potential that a lower toxicity threshold is required before clinical signs are evident,” say Drs. Gerken and Kuo.

How to treat dogs with chocolate toxicity

Your vet will determine treatment based on the type and amount of chocolate your dog ate, along with your pet’s size, age and medical history, sometimes using a toxicity calculator.

“Efforts should be made to have the dog vomit as quickly as possible,” say Drs. Gerken and Kuo, although vomiting should not be induced at home. “Ideally, this should be done with a veterinarian as we need to make sure that it is safe for your dog to vomit. Some dogs are already exhibiting neurologic signs and cannot protect their airway, putting them at risk for aspiration. Fluid therapy and activated charcoal should be administered because chocolate can be recirculated in the dog’s intestines and remain toxic for a longer time.”

There’s no question that dogs eating chocolate is an urgent situation, but the prognosis typically is good with prompt and appropriate treatment. Death by chocolate is rare for our canine companions, but we are wise to keep the sweet stuff inaccessible to them.