What Can Cats Not Eat? The Complete UK Guide to Safe & Unsafe Foods

Cats are naturally curious creatures - and that curiosity often extends to whatever you're eating. But unlike dogs, cats have a unique digestive system that makes certain everyday human foods genuinely dangerous for them. Some can cause serious illness. Others can be fatal, even in small amounts.

This guide covers everything UK cat owners need to know: the foods that are toxic and should never be given, the foods that are safe in moderation, and what to do if your cat gets into something they shouldn't. If your cat has eaten something you're not sure about, scroll to our emergency section at the bottom.

Foods Cats Should Never Eat

The following foods are toxic to cats and should be kept well out of reach at all times. Even small amounts of some of these can cause serious harm.

Chocolate

Chocolate is one of the most dangerous foods for cats. It contains theobromine and caffeine - both of which cats cannot metabolise effectively. Dark chocolate and baking chocolate are the most toxic, but milk chocolate and white chocolate can also cause problems. Symptoms of chocolate poisoning include vomiting, diarrhoea, rapid breathing, increased heart rate, seizures, and in severe cases, death.

There is no safe amount of chocolate for cats. If your cat has eaten any chocolate, contact your vet immediately. We cover this in more detail in our dedicated guide: can cats eat chocolate - full guide coming soon.

Onions, Garlic, Leeks and Chives

All members of the allium family - onions, garlic, leeks, chives, and shallots - are toxic to cats. They contain compounds called organosulfides that damage red blood cells and can cause a form of anaemia called Heinz body anaemia. This applies whether the food is raw, cooked, or powdered. Garlic powder is particularly dangerous because it's more concentrated.

Symptoms may not appear immediately - they can take several days to develop - which makes this especially easy to miss. Signs include lethargy, weakness, reduced appetite, pale or yellowish gums, and reddish or brown urine.

Grapes and Raisins

Grapes and raisins are well known to be toxic to dogs, but many cat owners don't realise they're equally dangerous for cats. Even tiny amounts have been reported to cause acute kidney failure. The exact mechanism isn't fully understood, which means there's no established "safe" dose. Avoid completely.

Xylitol

Xylitol is an artificial sweetener found in sugar-free chewing gum, some peanut butters, baked goods, and certain medications. In cats it can cause a rapid drop in blood sugar (hypoglycaemia) and liver failure. Check ingredient labels carefully on anything sugar-free before leaving it anywhere your cat can access.

Alcohol

Cats are far more sensitive to alcohol than humans. Even small amounts of beer, wine, spirits, or foods containing alcohol can cause vomiting, disorientation, breathing difficulties, and in severe cases, coma or death. Never give alcohol to a cat deliberately, and keep drinks out of reach.

Caffeine

Caffeine is toxic to cats and found in coffee, tea, energy drinks, some soft drinks, and certain medications. Signs of caffeine poisoning include restlessness, rapid breathing, heart palpitations, muscle tremors, and seizures. Keep coffee grounds and tea bags well away from cats - these are more concentrated sources than brewed drinks.

Raw Dough and Yeast

Unbaked bread dough containing yeast can be dangerous if ingested. The yeast continues to ferment in a cat's warm stomach, producing alcohol and causing the dough to expand - both of which can cause serious problems. Symptoms include bloating, discomfort, vomiting, and signs of alcohol toxicity.

Macadamia Nuts

Macadamia nuts are toxic to cats and can cause weakness, hyperthermia, vomiting, and tremors. As with grapes, the exact mechanism isn't fully understood, so complete avoidance is advised.

Raw Fish in Large Amounts

While small amounts of cooked fish are generally fine, raw fish contains an enzyme called thiaminase that destroys thiamine (Vitamin B1). A diet high in raw fish can lead to thiamine deficiency over time, causing neurological symptoms. Occasional raw fish is unlikely to cause harm, but it shouldn't be a regular feature of your cat's diet.

Liver in Large Amounts

Liver in small amounts is fine and actually nutritious for cats. However, too much liver can cause Vitamin A toxicity, which affects muscles and bones. This is a concern with regular feeding rather than occasional treats.

Foods That Are Safe for Cats in Moderation

Not all human foods are harmful - some can be offered as occasional treats. The key word is moderation. Treats should never make up more than 10% of your cat's daily calorie intake.

Cooked Chicken and Turkey

Plain cooked chicken or turkey - without seasoning, garlic, onion, or sauces - is one of the best human food treats for cats. It's high in protein and cats generally love it. Remove all bones before offering, as cooked bones can splinter and cause internal injuries.

Cooked Fish

Plain cooked salmon, tuna, or white fish is fine as an occasional treat. Avoid fish that's been seasoned or marinated. Tinned tuna in spring water (not brine or oil) is acceptable in small amounts, though it shouldn't be a regular fixture - it lacks certain nutrients cats need and can be high in mercury.

Eggs

Cooked eggs are a good source of protein and are safe for cats. Scrambled or boiled eggs with no butter, salt, or seasoning added are fine as an occasional treat. Raw eggs carry the risk of salmonella and the avidin in raw egg whites can interfere with biotin absorption - so always cook them first. We cover this in full in our dedicated guide: can cats eat eggs - full guide coming soon.

Certain Fruits

Some fruits are safe for cats in very small amounts - though most cats show little interest in sweet flavours as they lack the taste receptors to detect sweetness. Safe fruits include small pieces of watermelon (seeds removed), blueberries, peeled banana, and seedless apple. Fruits to avoid entirely include grapes, raisins, and citrus fruits. Our full guide covers safe and unsafe fruits for cats in detail.

Certain Vegetables

Some vegetables are safe and even beneficial. Cooked carrots, peas, and pumpkin are well-tolerated and occasionally added to commercial cat foods. Steamed broccoli and cooked green beans are also fine in small amounts. Avoid raw potatoes, tomato plants, and all members of the onion family.

Plain Cooked Rice

Plain cooked white or brown rice is safe for cats and is sometimes recommended by vets for cats with mild digestive upset. It's not nutritionally necessary for cats, but it's harmless as an occasional addition.

Cheese

This is a complicated one. Cheese is not toxic to cats, but most adult cats are lactose intolerant to varying degrees. Small amounts of hard cheese - like cheddar - are generally tolerated better than soft cheeses or milk, as hard cheese has lower lactose content. If your cat shows no digestive reaction, a tiny piece as an occasional treat is unlikely to cause harm. We go into much more detail in our full guide: can cats eat cheese - full guide coming soon.

Can Cats Drink Milk?

The image of a cat lapping up a bowl of milk is one of the most enduring in popular culture - and one of the most misleading. Most adult cats are lactose intolerant. After weaning, cats lose the enzyme lactase that's needed to digest lactose, the sugar found in cow's milk. Giving milk to a lactose-intolerant cat typically causes digestive upset - diarrhoea, vomiting, and stomach cramps.

If your cat loves milk, small amounts of specially formulated cat milk (which has had the lactose removed) are a safer alternative. Water should always be your cat's primary drink.

Can Cats Eat Dog Food?

Occasionally eating dog food won't harm a cat, but it's not suitable as a regular diet. Cats are obligate carnivores with specific nutritional requirements - including taurine, arachidonic acid, and Vitamin A - that dog food doesn't provide in adequate amounts. Long-term feeding of dog food to cats can lead to serious nutritional deficiencies.

Human Foods to Be Careful With

Beyond the clearly toxic foods, there are a number of common human foods that exist in a grey area - not necessarily toxic in small amounts, but potentially problematic with regular exposure:

• Salt - high sodium intake can cause excessive thirst, urination, and in large amounts, sodium poisoning. Avoid salty snacks like crisps and processed meats.
• Fat trimmings - both cooked and uncooked fat can cause pancreatitis in cats.
• Bones - cooked bones splinter and can cause choking or internal injuries. Raw bones carry bacterial risks.
• Sugary foods - cats don't need sugar and regular consumption contributes to obesity and dental disease.
• Spicy food - cats don't have spice receptors but capsaicin can still cause gastrointestinal irritation.
• Avocado - contains persin, which can cause vomiting and diarrhoea in cats.
• Coconut and coconut oil - small amounts are unlikely to cause harm but large amounts can cause digestive issues.

Toxic Plants Cats Should Avoid

Food isn't the only concern. Many common UK houseplants and garden plants are toxic to cats - sometimes fatally so. Lilies in particular are extremely dangerous: even small amounts of pollen from true lilies (Lilium species) can cause acute kidney failure in cats. Our full guide covers the top 15 toxic plants for cats and what to do if your cat eats one.

Can Cats Eat Grass?

Yes - and many cats actively seek it out. Eating grass is a normal cat behaviour. It's thought to help with digestion, provide trace nutrients, and act as a natural emetic when cats need to expel something from their stomach. Offering cat grass or growing your own wheatgrass is a safe way to satisfy this instinct indoors. We cover this in more detail in our guide on why cats eat grass and how to offer it safely.

Is Catnip Safe?

Yes - catnip (Nepeta cataria) is completely safe for cats. Not all cats respond to it (sensitivity is genetic - around 50-70% of cats are affected), but for those that do, the response is harmless and temporary. We cover this fully in our guides on whether catnip is dangerous and the benefits of catnip for cats.

What to Do If Your Cat Eats Something Toxic

If you suspect your cat has eaten something toxic, act quickly. Time matters with poisoning - the faster you get veterinary advice, the better the outcome is likely to be.

Step 1: Don't wait for symptoms to appear. Call your vet or an emergency animal poison line immediately.

Step 2: Try to identify what your cat ate and how much. If possible, bring the packaging or a sample to the vet.

Step 3: Do not try to make your cat vomit at home unless specifically instructed to by a vet - this can sometimes cause more harm.

Step 4: Monitor your cat closely and note any symptoms - vomiting, lethargy, seizures, changes in breathing or gum colour.

For a full guide on recognising signs of illness and when to seek emergency care, read our guide to the top 3 medical emergencies in cats.

How to Keep Your Cat Safe Around Food

A few practical habits go a long way:

• Keep bin lids secured - cats are capable of getting into unlidded bins and accessing scraps
• Never leave food unattended on worktops - especially anything from the toxic list above
• Brief anyone in the household - children especially may not know which foods are dangerous
• Check ingredient labels on anything processed before sharing - xylitol, onion powder, and garlic are often hidden ingredients
• If you have multiple pets, feed them separately - dog food and cat food aren't interchangeable

Frequently Asked Questions

What foods are toxic to cats?

The most dangerous foods for cats include chocolate, onions, garlic, grapes, raisins, xylitol (artificial sweetener), alcohol, caffeine, and raw dough. Even small amounts of some of these - particularly chocolate, onions, and grapes - can cause serious illness or death.

Can cats eat human food?

Some human foods are safe for cats in small amounts - cooked plain chicken, cooked fish, cooked eggs, and certain vegetables like peas and carrots. However, many everyday human foods are toxic to cats. If in doubt, stick to commercially prepared cat food and treats specifically formulated for cats.

Can cats eat cheese?

Cheese is not toxic to cats, but most adult cats are lactose intolerant to some degree. Small amounts of hard cheese are generally better tolerated than soft cheese or milk. If your cat shows no digestive reaction, an occasional small piece is unlikely to cause harm. See our full guide for more detail.

Can cats eat eggs?

Yes - cooked eggs are safe for cats and a good source of protein. Always cook eggs before offering them (scrambled or boiled with no added butter or seasoning). Raw eggs carry a risk of salmonella and can interfere with nutrient absorption.

Can cats eat bread?

Plain cooked bread is not toxic to cats in small amounts, but it has little nutritional value for them. Raw bread dough is dangerous - the yeast can ferment in a cat's stomach and produce alcohol. See our full guide for more detail.

Can cats eat strawberries?

Strawberries are not toxic to cats and are safe in very small amounts. However, cats are obligate carnivores and lack the sweet taste receptors to enjoy fruit - most cats will show no interest. Remove the leaves and stem and offer only a tiny piece if trying. See our full fruit guide for more detail: safe fruits for cats.

What should I do if my cat eats something toxic?

Contact your vet immediately - don't wait for symptoms. Try to identify what was eaten and how much. Do not attempt to make your cat vomit unless specifically instructed by a vet. For a full emergency guide, read our article on cat medical emergencies and first aid.

Can cats drink milk?

Most adult cats are lactose intolerant and cow's milk will cause digestive upset. Cat milk with the lactose removed is a safer alternative if your cat enjoys milk. Water should always be their primary drink.

Is it safe for cats to eat dog food?

Occasionally eating dog food won't cause immediate harm, but it's nutritionally inadequate for cats long term. Cats have specific dietary requirements - including taurine - that dog food doesn't meet in sufficient quantities.