What the numbers mean
Chocolate poisoning is methylxanthine poisoning — theobromine and caffeine together. Merck’s doses, in milligrams of methylxanthines per kilogram of dog:
- 20 mg/kgVomiting, diarrhea, drinking and weeing more than usual.
- 40–50 mg/kgThe heart starts racing and going out of rhythm.
- 60 mg/kg and upSeizures.
- 100–200 mg/kgThe reported LD50. Merck notes deaths well below it.
Signs usually turn up 6 to 12 hours after eating, which is the trap: the dog is fine all evening and bad at four in the morning. Do not wait for the first sign before calling.
Why the type matters so much
The same weight of chocolate can be twelve times the dose depending on what it is. These are the figures the calculator uses, from Merck:
| Type | Per gram | Per ounce |
|---|---|---|
| Cocoa powder | 28.5 mg | 807 mg |
| Unsweetened baking chocolate | 15.5 mg | 440 mg |
| Cocoa bean hulls, garden mulch | 9 mg | 255 mg |
| Dark and semisweet | 5.3–5.6 mg | 150–160 mg |
| Milk chocolate | 2.3 mg | 64 mg |
| White chocolate | 0.04 mg | 1.1 mg |
White chocolate is the odd one. At 0.04 mg per gram a dog would have to eat its own body weight in it to reach a stomach-upset dose. The fat and sugar will still make it sick — just not from theobromine.
Cocoa bean mulch is the one people forget. It is sold as garden bark, it smells like chocolate, and dogs eat it off the flowerbed.
What to actually do
- Find the wrapper. Percentage cocoa and net weight are the two numbers that decide everything.
- Guess the amount high, not low. If the bag might have been full, treat it as full.
- Call before signs start, not after. Emptying the stomach is a vet job and it works best early.
- Do not give hydrogen peroxide, salt or anything else at home unless a vet on the phone talks you through it. Peroxide burns the stomach lining and it is no longer a routine first move.
- Take the packet with you.
What about cats
Cats are more sensitive to methylxanthines than dogs are, and it almost never happens, because cats cannot taste sweetness and mostly will not eat chocolate. If a cat has eaten it, ring — the numbers on this page are the canine ones.