Caffeine and theobromine in chocolate
Chocolate contains both, in much smaller amounts than coffee — and theobromine is the reason chocolate is dangerous to dogs.
If you read nothing else
Chocolate contains theobromine and a smaller amount of caffeine, both scaling with cocoa solids. The consequential fact is that theobromine is toxic to dogs at doses harmless to people.
Two related compounds
Cacao contains theobromine and caffeine, both methylxanthines. Theobromine is present in considerably larger quantities and is the dominant one; caffeine is a minor component by comparison.
Theobromine has a milder, longer-lasting stimulant effect than caffeine, which is part of why chocolate does not feel like coffee even at meaningful doses.
How much is in a bar
Content scales with cocoa solids, so a high-percentage dark bar has substantially more than a milk bar, and white chocolate has essentially none.
As an order of magnitude, the caffeine in a dark chocolate bar is a fraction of a cup of coffee's. Someone sensitive to caffeine may notice an evening dark chocolate; most people will not. Precise figures vary by origin, processing and formulation and are not printed on packaging.
Why it matters for dogs
Dogs metabolise theobromine far more slowly than humans do, so it accumulates to toxic levels at doses that are unremarkable for a person. This is the one genuinely urgent piece of chocolate safety information there is.
Dark chocolate and cocoa powder are the most dangerous because their theobromine content is highest; cocoa shell mulch is dangerous for the same reason. A dog that has eaten chocolate is a veterinary matter, and the amount and the dog's weight both matter.
Practical notes for people
If you are avoiding caffeine, white chocolate contains essentially none and milk chocolate contains little. High-percentage dark is where the amounts become worth thinking about.
Beyond that, this is a low-stakes question for most adults. Anyone managing a medical condition or a medication interaction should raise it with a clinician rather than working from general figures.
Covered in this guide
- Chocolate and catsThe same compound, and the pets the dogs record does not cover.
- Chocolate and sleepThe practical question the methylxanthine content raises.
- Chocolate and childrenDose per kilogram, and the sugar-behaviour belief.
- Caffeine and theobromine in chocolateThe evidence-graded record for the human effects.
- Chocolate, theobromine and dogsThe record covering the veterinary risk in detail.
- Cocoa powderThe highest-concentration product, and the one most often left within reach.
Sources
- ChocolateHQ editorial synthesis — ChocolateHQ(citation identity confirmed; passage not re-read)