How Much Chocolate Is Toxic to a Dog? A Chart by Weight and Type

The candy bowl is by the front door. The kids' haul is about to come home by the pound. Your dog has noticed both.

If your dog gets into the chocolate, how serious it is depends on what kind, how much, and your dog's size and health. When it happened matters too, because it changes what your vet can still do. Here is how little chocolate it can take to cause trouble, and what to do in the first few minutes.

Why chocolate is toxic to dogs

Chocolate contains two related stimulants, theobromine and caffeine. The Merck Veterinary Manual, in a chapter written by a veterinarian at the ASPCA's poison control center, says chocolate holds 3 to 10 times as much theobromine as caffeine, and that both contribute to the poisoning. They stimulate the nervous system, make a dog pee more and speed up the heart.

Dogs clear theobromine slowly, too. Merck puts its half-life in dogs at 17.5 hours, the time it takes to get rid of just half of it. And dogs are the most common patients, thanks to what Merck calls their "indiscriminate eating habits." If you have ever watched a dog inhale something off the kitchen floor, you know.

Not all chocolate is equal

The darker the chocolate, the greater the risk, according to the ASPCA. Here is roughly how much theobromine and caffeine, combined, Merck lists for each type:

• Cocoa powder: about 807 mg per ounce, the most of anything on Merck's list.
• Unsweetened baking chocolate: about 440 mg per ounce.
• Dark chocolate bars: it depends on the percentage on the label. Merck's example, a 65% bar, has about 286 mg per ounce.
• Semisweet and sweet dark chocolate: about 150 to 160 mg per ounce.
• Milk chocolate: about 64 mg per ounce.
• White chocolate: about 1.1 mg per ounce, which Merck calls a negligible source of these stimulants.

That percentage is worth reading. Merck explains that it tells you how much unsweetened chocolate is in the bar, so a 65% bar is roughly two-thirds baking chocolate, and higher numbers get closer still. Real amounts also vary by brand and even by bean, so Merck calls its figures general guidelines, not a lab result for the bar on your counter.

How little it takes: the chart

This chart answers one question: roughly how little of each type can start causing trouble. Each number is about the amount at which Merck says mild signs, like vomiting, diarrhea and excessive thirst, may begin: 20 mg of theobromine and caffeine per kilogram of your dog's weight. The inputs are Merck's, the arithmetic is ours, and we rounded every result down.

Wrapper in grams? One ounce is about 28 grams.

How to read it:

• About twice the amount reaches the range where Merck says heart effects occur (40 to 50 mg per kilogram). About three times reaches the seizure range (60 mg per kilogram and up).
• Dogs vary. Merck notes that sensitivity differs from one dog to the next. These are general guidelines, not a promise about yours.
• It leaves out the extras. Fat, raisins, macadamia nuts and the sweetener xylitol are separate problems (more below).

So what is the chart for? It shows how little of the dark stuff it takes. It is not a tool for deciding to wait and see. Pet Poison Helpline's experts run this math with your dog's real weight and health and the actual product, then tell you whether your dog can be watched at home or should see a vet. Let them.

The signs, and when they show up

Here is the sneaky part. Merck says signs usually show up within 6 to 12 hours of eating chocolate. A dog can seem completely fine for hours.

• Early: excessive thirst, vomiting, diarrhea, a swollen belly and restlessness.
• Later: hyperactivity, peeing a lot, a wobbly walk, stiffness, tremors and seizures.
• Heart and breathing: Merck's pet owner guide also lists a very fast and irregular heartbeat, fast breathing, high blood pressure, fever, a bluish tinge to the skin and gums, and coma.

In severe cases, signs can last up to 72 hours. Chocolate is also fatty, and Merck notes the fat may trigger pancreatitis in susceptible dogs, one more reason even white chocolate deserves a call. If you see diarrhea, mention it. (More on loose stool in why is my dog's poop runny.)

Go straight to the nearest veterinary hospital if your dog is having seizures, has trouble breathing, or is unconscious or not responding to you. That is the ASPCA's advice, and it says to bring the packaging with you.

What to do right now

1. End the buffet. Move your dog away from the chocolate. The ASPCA says to check on your other pets too, even ones you do not think were involved.
2. Keep the evidence. Save the wrapper, box or bag, and any leftovers. If your dog threw up, the ASPCA suggests checking whether the chocolate is in it.
3. Call now, even if your dog seems fine. Call your vet or a poison line below. The ASPCA's advice is not to wait: many poisons can be slow to show, and treatment can get harder once symptoms start.
4. Do not make your dog vomit unless you are told to. Pet Poison Helpline's emergency instructions say not to induce vomiting without consulting a vet or the helpline, and not to give home antidotes. The ASPCA notes that for some dogs, such as flat-faced breeds with breathing issues, vomiting at home may not be safe. If home care is right for your dog, the expert on the phone will walk you through it.

Both poison lines are open around the clock:

• ASPCA Poison Control: (888) 426-4435. Open 24 hours a day, 365 days a year, and a consultation fee may apply.
• Pet Poison Helpline: (855) 764-7661. Also 24/7. It lists a $99 fee per incident, with follow-up consultations included.

Why not wait and see? Merck's guidance for vets is to consider making a dog vomit when the chocolate was eaten recently, for example within 2 hours, while the dog still seems normal. Signs usually show up within 6 to 12 hours. Our reading of those two numbers: if you wait for signs, the best window may already be closed. As Pet Poison Helpline puts it: "The sooner an exposure or poisoning is addressed, the easier, less expensive, and safer it is to treat."

One more ASPCA point worth repeating: acting in a hurry on something you read online can sometimes make things worse for your pet. Yes, that includes this article. Use it to understand the risk, and let a professional make the call.

What to tell the vet

There is no readily available test for chocolate poisoning, Merck notes, so the diagnosis rests on what happened and on your dog's signs. A lot of it rests on you. Have this ready:

• What kind. Milk, dark, semisweet, baking chocolate, cocoa powder or white. If the label lists a cocoa percentage, read it out.
• How much. Count the wrappers and check how much of the bar or bag is gone. The ASPCA asks you to note the amount.
• When. The time it happened, or your best guess at the window.
• Your dog. Weight, age, breed and health history. Poison control will ask for all of it.
• What else was in it. Pet Poison Helpline warns that chocolate treats may hide other poisons too, such as macadamia nuts, raisins or the sweetener xylitol. Each is its own problem. We cover xylitol and raisins in what fruit can dogs eat.
• What has happened since. Any vomiting, diarrhea or restlessness, and anything you already tried at home.

If you head to the clinic, take the wrapper (or a photo of it). The ASPCA says the packaging helps the vet treat your dog.

Chocolate-proof the season

Halloween is only the opening act. A study of UK vet records found chocolate cases were far more common around Christmas and, to a lesser extent, Easter. (Halloween was not a clear spike there, though the authors note US and German reviews have described one.)

• Find the stash. The ASPCA warns that kids often stash candy in their bedrooms, and a dog can sniff out almost any hiding spot. Ask where it is, then move it.
• Up and closed. Candy bowls go up high, trick-or-treat bags go in a closed cupboard, and wrappers go in a trash can with a lid.
• Watch the baking shelf. Cocoa powder and baking chocolate are the most concentrated forms, and holiday baking brings them out. Brownies, cakes and hot cocoa count too. Their strength depends on the recipe, so have the recipe or box handy for the call.
• Keep the leash short after Halloween. Dropped candy may still be on the sidewalk, and if your dog treats the sidewalk as a buffet (some dogs even eat poop), keep them close. Our Halloween safety guide covers the rest of the night, from costumes to the doorbell.

The bottom line

Darker is worse, smaller dogs need less, and the clock starts when the wrapper hits the floor. Keep the chocolate out of reach, keep this chart for perspective, and save both poison control numbers in your phone today.

And since the walks do not stop for the holidays, take the quiz to see how many bags your dog actually needs each month, or grab a box so you are set for the season.

This article is general information, not veterinary advice. If your dog eats chocolate of any kind, in any amount, call your vet, ASPCA Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661 right away.

Sources

• Merck Veterinary Manual, Chocolate Toxicosis in Animals, professional version, by Cristine Hayes, DVM, ASPCA Animal Poison Control Center (reviewed September 2024, updated February 2026)
• Merck Veterinary Manual, Food Hazards, pet owner version
• ASPCA, ASPCA Poison Control
• ASPCA, People Foods to Avoid Feeding Your Pets
• ASPCA, What to Do if Your Pet Is Poisoned, March 20, 2019
• ASPCA, What to Expect When Calling ASPCA Poison Control, April 1, 2020
• ASPCA, My Pet Ate Something! When Should I Seek Help?, June 9, 2023
• ASPCA, Halloween Safety Tips
• Pet Poison Helpline, 24/7 Animal Poison Control Center (emergency instructions and fee)
• Pet Poison Helpline, Chocolate
• Noble PJM, Newman J, Wyatt AM, Radford AD, Jones PH. Heightened risk of canine chocolate exposure at Christmas and Easter. Veterinary Record, 2017; 181(25): 684