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The Morning-After · Pet emergencies · Free tool

Your dog ate chocolate. How worried should you be?

Chocolate poisons dogs in proportion to their size and the cocoa content. A few stray M&Ms off the party floor usually isn't the same emergency as a square of baking chocolate. Tell us the details and we'll estimate the dose against the Merck Veterinary Manual thresholds, so you know how fast to move.

☎️ You can call right now. You don't have to wait for symptoms

This tool helps you gauge urgency while you reach them. It is not a diagnosis.

Quick answer: chocolate's danger scales with your dog's weight and the cocoa content. Trouble starts near 20 mg of theobromine per kg (stomach upset), 40 mg/kg (heart effects), and 60 mg/kg (seizures). A few milk-chocolate chips rarely matters; an ounce of dark or baking chocolate in a small dog can. Enter the details below, and when in doubt, call.

A pug sitting at a table looking up, hoping for human food
The begging face is cute, but the party table is where most chocolate accidents start. Photo: Karin Hiselius / Unsplash.

Not sure? Pick the darkest it could be. That's the safer guess.

A standard chocolate bar is about 1.5 oz (43 g); one Hershey's Kiss is ~0.16 oz (4.5 g).

Why the same square is fine for one dog and an ER trip for another

Two things decide how dangerous chocolate is: how much theobromine is in it, and how big the dog is. Theobromine is a methylxanthine. A stimulant dogs clear very slowly, and the darker and more bitter the chocolate, the more of it there is.

A bar of dark chocolate broken into squares on a dark surface
Per ounce, baking chocolate carries roughly seven times the theobromine of a milk-chocolate bar. Photo: Towfiqu barbhuiya / Unsplash.

Theobromine by chocolate type

These are the methylxanthine figures from the Merck Veterinary Manual, per ounce:

  • White chocolate: ~1 mg/oz (essentially no theobromine risk, but high fat)
  • Milk chocolate: ~64 mg/oz
  • Dark / semisweet: ~150–160 mg/oz
  • Baking / unsweetened: ~440 mg/oz
  • Cocoa powder: ~807 mg/oz

The math, and where it comes from

We multiply the amount eaten by the theobromine density for that chocolate type to get the total dose in milligrams, then divide by your dog's weight in kilograms to get mg per kg. We compare that to the canine thresholds the Merck Veterinary Manual reports:

  • ~20 mg/kg, mild signs: vomiting, diarrhea, thirst, restlessness
  • ~40 mg/kg, cardiotoxic: racing or abnormal heart rhythm
  • ~60 mg/kg, seizures and life-threatening signs
  • 100–200 mg/kg, the reported LD50 (often fatal)

For dark chocolate we use the upper end of the published range, so the estimate leans cautious. Even so, the safest move for any real ingestion is a phone call. The number on this page is a guide, not a green light.

The other party-table hazards

Chocolate isn't the only thing that lands a dog at the vet after a party. Xylitol (birch sugar, in many sugar-free treats), grapes and raisins, macadamia nuts, onion and garlic, and alcohol or yeast dough are all dangerous. If you're not sure what they got into, our pet toxic-food checker walks through the common ones, and the treat calorie calculator keeps the safe stuff in check.

Worth keeping on hand for next time: a pet first-aid kit and the poison-control number saved in your phone. As an Amazon Associate we earn from qualifying purchases.

FAQ

My dog just ate chocolate. What should I do right now?

Don't wait for symptoms. Note what kind of chocolate, roughly how much, and when, then call your vet, the Pet Poison Helpline (855-764-7661), or the ASPCA Animal Poison Control Center (888-426-4435). They'll tell you whether to monitor at home or come in. This calculator helps you gauge urgency while you reach them. It is not a substitute for that call.

How much chocolate is toxic to a dog?

It depends on the dog's weight and the type of chocolate. Toxicity tracks theobromine (a methylxanthine). Per the Merck Veterinary Manual, mild stomach signs start around 20 mg of theobromine per kg of body weight, heart effects around 40 mg/kg, and seizures at 60 mg/kg or more. Because dark and baking chocolate carry far more theobromine than milk chocolate, a small amount of baker's chocolate is far more dangerous than the same weight of a milk-chocolate bar.

How long after eating chocolate do symptoms show up?

Signs usually begin within 6 to 12 hours and can last 24 to 72 hours because theobromine is cleared slowly. Early signs are vomiting, diarrhea, restlessness, and increased thirst and urination; more serious signs are a racing or irregular heartbeat, tremors, and seizures. Theobromine also gets reabsorbed from the bladder, so a vet may keep your dog longer than you'd expect.

Is white chocolate dangerous?

White chocolate has almost no theobromine (about 1 mg per ounce), so theobromine poisoning is unlikely from it. But it's still very high in fat and sugar, which can trigger vomiting, diarrhea, or pancreatitis, and many white-chocolate products contain other hazards like macadamia nuts or xylitol. 'Low theobromine' is not the same as 'safe.'

What about cats?

Cats can be poisoned by chocolate too, and they're at least as sensitive as dogs. They just rarely choose to eat it. The published mg/kg thresholds come from canine data, so for a cat, treat any real ingestion as urgent and call your vet or a poison line rather than relying on a number.

Sources

This calculator is an educational risk-assessment guide, not veterinary advice or a diagnosis. The amount actually eaten is usually uncertain, individual dogs vary, and chocolate products often hide other hazards. Always contact your veterinarian or a poison-control line for any real ingestion. Thresholds and potency figures from the Merck Veterinary Manual; methodology last verified 2026-06-24.