Why chocolate and dogs do not mix
Chocolate contains theobromine, a stimulant that humans clear quickly and dogs clear slowly, so it builds up and overstimulates the heart and nervous system. The concentration climbs steeply with darkness: cocoa powder and baking chocolate are the most potent, plain dark chocolate comes next, milk chocolate carries much less per gram, and white chocolate contains barely any. That is why 'he ate some chocolate' is never enough information — a few squares of a high-cocoa bar stolen by a small terrier is a more serious event than a large retriever licking up the same weight in milk chocolate buttons.
Gather the three facts before you dial
Your vet's first questions are predictable, so answer them in your first sentence. What type: keep the wrapper and read the cocoa percentage or product name off it. How much: weigh or count what remains, check for a second raided source such as a selection box, and be honest about the maximum he could have taken. How heavy is your dog: a current weight, not last year's guess. Then note the time — chocolate eaten twenty minutes ago offers more options than chocolate discovered after a day at work — and phone for advice immediately rather than watching and worrying at home.
What signs look like, and when they appear
Early signs are usually restlessness, panting, drooling, vomiting, and diarrhoea, often starting within a few hours. A dog who has taken a larger amount can progress to a racing or irregular heartbeat, muscle tremors, wobbliness, and in severe cases seizures, which is why a dog who merely looks hyper and sorry for himself still deserves a prompt call rather than a wait-and-see evening. Do not offer milk, bread, or home remedies to 'soak it up', and do not induce vomiting unless a veterinary professional directs it for this case — a trembling, agitated dog can inhale vomit, and some situations call for clinic treatment instead.
While you wait and after you are seen
Keep your dog calm, warm, and away from further food raids; excitement and a full stomach both complicate the picture. If the vet wants him in, bring the wrapper, a note of timings, and a sample of vomit only if they ask for it. After treatment or a watch-at-home plan, expect a subdued day or two, keep water available, and phone back if vomiting restarts, tremors appear, or he becomes unusually quiet, because effects can linger while the theobromine clears. Tell the household what happened in plain terms: the next bar of baking chocolate goes in a tin, on a shelf, behind a door.
Prevention that survives real life
Dogs find chocolate where celebrations put it: advent calendars at nose height, Easter eggs in carrier bags, baking supplies on worktops, gifts under trees, and handbags after a shopping trip. Walk your kitchen and living room at dog height after every festival shop and move the lot into closed, high storage. KinsLe's Pet Passport keeps your dog's records together in one portable packet — weight, history, and regular clinic included — so on the day a wrapper is found empty on the floor, the facts your vet needs are already gathered instead of hunted for.