Chocolate and dogs: the toxic dose by weight and chocolate type
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
If your dog has just eaten chocolate, note the time, the type of chocolate (check the label for the cocoa percentage) and how much is missing, then call your vet or an animal poison helpline straight away — in the US the ASPCA Animal Poison Control Center, (888) 426-4435 (a consultation fee may apply), in the UK Animal PoisonLine, 01202 509 000, in France the CNITV in Lyon, 04 78 87 10 40. Do not make your dog vomit yourself: that is the vet’s call, and it works well while the chocolate is still in the stomach. The good news is that severity can be calculated: it depends on the dog’s weight and on the chocolate’s theobromine content, and many ingestions stay below the toxic threshold. The table below helps you gauge the risk before you call; it does not replace your vet’s advice.
Contents · 7 sections
Why chocolate is toxic to dogs
Cocoa contains two methylxanthines, theobromine and, in smaller amounts, caffeine. Dogs clear them much more slowly than humans do: they build up, stimulate the nervous system and the heart, and irritate the gut. According to the Merck Veterinary Manual, the vets’ reference, mild signs (vomiting, diarrhoea, thirst) appear at around 20 mg of methylxanthines per kilo of body weight, heart effects at 40 to 50 mg/kg and seizures from 60 mg/kg. Signs usually start 6 to 12 hours after ingestion, so a dog that looks fine one hour later is not out of the woods.
The darker the chocolate, the more dangerous it is
Methylxanthine content varies roughly 700-fold between white chocolate and cocoa powder. Reference values: white chocolate 0.04 mg per gram, milk chocolate 2.3 mg/g, dark “semisweet” chocolate (50-60% cocoa) 5.3 to 5.6 mg/g, unsweetened baking chocolate 15.5 mg/g and unsweetened cocoa powder 28.5 mg/g (Merck Veterinary Manual). For a 70-85% dark bar, the USDA FoodData Central database lists 802 mg of theobromine and 80 mg of caffeine per 100 g, about 8.8 mg/g.
Table: how much chocolate is a concern
From these contents we calculated the amount of chocolate that brings a dog to the threshold for first signs (20 mg/kg) and then to the heart-effect threshold (40 mg/kg). How to read it: a 10 kg dog that eats 23 g of 70-85% dark chocolate reaches the first-signs threshold; at 45 g the heart can be affected.
| Dog’s weight | Milk chocolate | Dark 50-60% | Dark 70-85% | Baking chocolate 100% | Cocoa powder |
|---|---|---|---|---|---|
| 5 kg (11 lb) | 43 g / 87 g | 18 g / 36 g | 11 g / 23 g | 6.5 g / 13 g | 3.5 g / 7 g |
| 10 kg (22 lb) | 87 g / 174 g | 36 g / 71 g | 23 g / 45 g | 13 g / 26 g | 7 g / 14 g |
| 20 kg (44 lb) | 174 g / 348 g | 71 g / 143 g | 45 g / 91 g | 26 g / 52 g | 14 g / 28 g |
| 30 kg (66 lb) | 261 g / 522 g | 107 g / 214 g | 68 g / 136 g | 39 g / 77 g | 21 g / 42 g |
| 40 kg (88 lb) | 348 g / 696 g | 143 g / 286 g | 91 g / 181 g | 52 g / 103 g | 28 g / 56 g |
First figure: first-signs threshold (20 mg/kg). Second figure: heart-effect threshold (40 mg/kg). A standard bar weighs 100 g (about 3.5 oz). These thresholds are population benchmarks: an older dog, a dog with heart disease or a very small dog may react sooner, and cakes, spreads or chocolate drinks add fat and sugar that can inflame the pancreas. When in doubt, call: the vet decides.
What clinic data show
A study by Noble and colleagues, published in 2017 in the Veterinary Record, analysed records from 229 UK veterinary practices in the SAVSNET network between 2012 and 2017 (see the study). Across 386 chocolate exposures, the risk was about 4.7 times higher at Christmas and nearly twice as high at Easter as during the rest of the year. More than half of the dogs (56%) were seen within six hours, and among cases where the dose could be estimated, 41% were below the 20 mg/kg threshold: calling early often avoids heavy treatment.
Signs to watch for
- In the first hours: vomiting, diarrhoea, increased thirst and urination, restlessness, panting.
- More serious signs: a very fast or irregular heartbeat, tremors, stiffness, a drunken gait, seizures. They call for an immediate visit, day or night.
- Duration: because theobromine is cleared slowly, signs can last more than a day; your vet may keep the dog under observation.
Prevention beats cure
- Keep chocolate, Advent calendars, Easter eggs and cocoa high up or in a closed cupboard, never in a bag on the floor.
- Tell guests and children: no “little square” for the dog, not even milk chocolate.
- Watch out for cakes and desserts left on the coffee table, and for wrappers in the bin.
- To treat your dog, choose treats made for dogs: our guide to dog training treats gives benchmarks, and the dog food section gathers our advice. Common mistakes with young dogs are covered in puppy feeding mistakes.
Frequently asked questions
My dog ate a square of milk chocolate — is it serious?
A square of milk chocolate (about 5 to 10 g) is well below the first-signs threshold for a medium-sized dog, but not necessarily for a 2 or 3 kg dog. Note the amount and call your vet or a poison helpline: they work out the exact dose in minutes.
Is white chocolate safe for dogs?
It contains almost no theobromine, but it is very fatty and sugary: a large amount can cause digestive upset or even pancreatitis. It is not dog food.
How long after eating chocolate does a dog get sick?
Signs most often appear 6 to 12 hours after ingestion and can last more than a day. That is why you should call as soon as you find out, without waiting for symptoms.
Should I make my dog vomit after eating chocolate?
Not yourself: home remedies (salt, hydrogen peroxide) are dangerous. The vet can induce vomiting with a suitable drug if the ingestion is recent and the dose warrants it.
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This guide is part of Planète Pets’s Dogs universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.
