Foods Toxic to Dogs: The Complete Guide to Canine Food Safety
Dogs are opportunistic eaters with a tendency to consume almost anything within reach, which makes food toxicity one of the most common causes of emergency veterinary visits. Many foods that are perfectly safe for humans are genuinely dangerous to dogs — some lethally so. This guide covers the most important food hazards, explains why they cause harm, and tells you exactly what to do if your dog is exposed.
Highest Priority: Treat as an Emergency
Grapes, Raisins, Sultanas, and Currants
There is no safe dose of grapes or any of their dried forms for dogs. Even a small amount can cause acute kidney failure, and because individual sensitivity varies enormously, it is impossible to predict which dogs will be severely affected. Some dogs have eaten a significant quantity without apparent harm; others have died after eating just a few raisins. Do not gamble on your dog's tolerance.
Research published in 2021 in Toxicology Communications identified tartaric acid as the likely toxic agent, which also implicates cream of tartar and tamarind as potential hazards. Symptoms include vomiting and diarrhoea within hours, followed by lethargy, loss of appetite, abdominal pain, decreased urination, and progressive kidney failure.
A particular seasonal danger exists in the UK and Europe: foods containing raisins or currants are extremely common around Christmas and Easter. Christmas pudding, mince pies, hot cross buns, and Christmas cake all contain dried vine fruits and must be kept entirely out of reach of dogs.
Xylitol
Xylitol is an artificial sweetener found in a wide range of products including sugar-free chewing gum, some brands of peanut butter, sugar-free baked goods, vitamin supplements, medications, nasal sprays, and oral hygiene products. In dogs, xylitol triggers a rapid and massive release of insulin, causing life-threatening hypoglycaemia (dangerously low blood sugar) within 15 to 30 minutes of ingestion. At higher doses, it also causes acute liver failure, which can be fatal even when blood sugar is managed.
Always read the full ingredient list on any sugar-free product in your home. If you give your dog peanut butter as a treat or to administer medication, check the label every time — formulations change, and some major brands have added xylitol. Any suspected xylitol ingestion is a veterinary emergency requiring immediate treatment.
Onions, Garlic, Leeks, and Chives
All members of the allium family are toxic to dogs in all forms: raw, cooked, dried, and powdered. They contain thiosulphate compounds that damage the membranes of red blood cells, causing haemolytic anaemia — a condition in which red blood cells are destroyed faster than the body can produce them. Dried and powdered forms are more concentrated and therefore more dangerous per gram than fresh.
Toxicity is cumulative. Regular small amounts over time are just as dangerous as a single large dose, so feeding your dog food scraps that habitually contain onion or garlic carries a real risk. Be particularly vigilant with gravies, soups, sauces, and prepared meat dishes, which frequently contain onion or garlic. Signs of toxicity include lethargy, weakness, pale or yellowish gums, reduced appetite, and reddish-brown urine.
Serious Toxins Requiring Veterinary Attention
Chocolate
Chocolate is toxic to dogs because they metabolise theobromine — a stimulant naturally occurring in cacao — far more slowly than humans. The darker the chocolate, the higher the theobromine content and the greater the risk. Baking chocolate and dark chocolate are significantly more dangerous than milk chocolate, but all chocolate poses a risk at sufficient doses.
Symptoms include vomiting, diarrhoea, excessive thirst and urination, restlessness, hyperactivity, muscle tremors, and in severe cases, seizures and cardiac arrhythmias. The dose matters significantly: a small dog eating even a modest amount of dark chocolate can develop serious symptoms. If your dog has eaten chocolate, contact your vet with details of your dog's weight, the type of chocolate, and the estimated amount consumed — they can calculate whether the dose is likely to be toxic.
Macadamia Nuts
Macadamia nuts cause a distinctive toxidrome in dogs that includes vomiting, muscle weakness (particularly in the hind limbs), tremors, and hyperthermia (elevated body temperature). The mechanism of toxicity is not yet understood, but the syndrome is well-recognised. While macadamia nut toxicosis is rarely fatal, it is extremely unpleasant for the dog and veterinary supportive treatment is usually required. Never offer macadamia nuts as treats and check ingredients in biscuits and confectionery.
Alcohol
Dogs are far more sensitive to ethanol than humans and have no tolerance for alcohol. Even small amounts can cause significant toxicity, including vomiting, disorientation, incoordination, respiratory depression, dangerously low blood sugar, low body temperature, and coma. Sources include beer, wine, spirits, alcoholic cocktails, fruit cake soaked in spirits, and — less obviously — unbaked bread dough, in which yeast fermentation produces ethanol in the stomach. Keep all alcoholic products and raw dough securely away from dogs.
Caffeine
Coffee, tea, energy drinks, cola, and some medications contain caffeine, which is toxic to dogs at relatively low doses. Signs of caffeine toxicity include restlessness, rapid breathing, muscle tremors, elevated heart rate, and in severe cases, seizures. Keep coffee grounds, used teabags, and energy drinks out of reach — dogs may be attracted to the smell.
Other Hazards to Be Aware Of
Avocado
Avocado contains persin, a toxin primarily concentrated in the skin, stone, and leaves of the plant. The flesh of the avocado carries a lower persin concentration, but it is still advisable to avoid feeding it to dogs. Ingestion of the stone also presents a serious choking and obstruction hazard.
Nutmeg
Myristicin, found in nutmeg, can cause disorientation, hallucinations, elevated heart rate, and seizures in dogs when consumed in significant quantities. Small amounts in cooked food are unlikely to cause harm, but pure or concentrated nutmeg should never be given deliberately.
Salt and Sodium-Rich Foods
Excessive salt intake causes sodium ion poisoning in dogs, with symptoms including excessive thirst and urination, vomiting, diarrhoea, tremors, elevated temperature, and seizures. Avoid giving dogs crisps, salted snacks, and highly processed foods.
Fruit Stones and Apple Seeds
Stones from cherries, plums, peaches, and apricots, as well as apple and pear seeds, contain amygdalin — a cyanogenic glycoside that releases cyanide when chewed and crushed. Swallowing a stone whole carries primarily an obstruction risk; the toxic risk arises when the stone is broken open. Remove stones from fruit before allowing dogs any access.
Cooked Bones
Cooked bones are not a toxin, but they are a serious physical hazard. Cooking causes bones to become brittle, meaning they splinter into sharp shards that can perforate the oesophagus, stomach, or intestines, or cause life-threatening obstructions. Never give your dog cooked bones of any kind. If you wish to offer raw meaty bones, discuss appropriate choices with your vet first.
What to Do in a Food Emergency
- Act immediately — do not wait for symptoms to develop. Call your vet or an animal poison helpline straight away.
- In the UK, contact the Animal Poison Line on 01202 509000 (a fee applies) or the VPIS via your vet.
- Note the time of ingestion, the food involved, and as accurate an estimate of the quantity as possible.
- Do not induce vomiting unless explicitly instructed by a vet — it is not always appropriate and can worsen some situations.
- Bring the packaging of any product to the vet so the full ingredient list can be checked.
Preventing food toxicity requires consistent vigilance. Keep dangerous foods in secured cupboards, educate all household members including children about what dogs cannot eat, and be especially careful during festive periods when hazardous foods such as chocolate, dried fruit, and alcohol are more widely present in the home.