It might be tempting to indulge your cat's begging and sneak it occasional scraps, but this could actually do them more harm than good. If you're feeding it the correct measurement of commercial cat food, then your pet will be getting all the nutrients it needs from that. Adding treats and scraps from your plate will not only increase the risk of obesity and dental decay, but could also be poisonous to your cat and cause serious health problems or even death – so no matter how many times it meows, just remember that saying no is for its own good! If your cat appears unwell, always consult a vet.

These are very toxic to cats due to their content of n-propyl disulphide, which can break down its red blood cells causing anaemia. Be especially wary of onion or garlic powder hidden in sauces and processed foods.

Symptoms: fainting, discoloured urine, lethargy and pale gums.

Treatment: removing onion or garlic from your cat's diet should ensure a full recovery, although in severe cases a blood transfusion may be required.

While a saucer of milk might seem like staple fare for a cat, many adult cats are actually lactose intolerant and should avoid dairy products.

Symptoms: an upset stomach and diarrhoea.

Treatment: removing dairy products from your cat's diet should be sufficient.

It probably goes without saying that you shouldn't give alcohol to your cat – just a tiny amount of any strong spirit can damage the liver and brain, cause a coma or even death – but ethanol poisoning can occur from eating fermented fruits, solvents or even bread dough.

Symptoms: loss of bladder control, breathing difficulties, drowsiness, bloating, vomiting.

Treatment: take your cat to a vet immediately.

They may seem harmless, but grapes and raisins can make your cat sick - large amounts can even cause kidney failure.

Symptoms: some cats may be unaffected, while others will experience diarrhoea, lethargy, vomiting and even death.

Treatment: if your cat is showing ill effects, take them to a vet immediately.

You might not be able to function without your morning brew, but coffee could be fatal to your cat. Keep caffeine products away from your pets – and be careful when throwing out coffee grounds, chocolate wrappers and anything else that your cat may be able to find in the rubbish.

Symptoms: hyperactivity, vomiting, a raised heart rate, seizure, tremor and collapse.

Treatment: seek treatment from a vet immediately. Do not attempt to induce vomiting at home.

Many sweet products such as gum, baked goods and confectionary contain a sweetener called xylitol. Ironically, this can cause your cat's blood sugar to drop by increasing insulin production.

Symptoms: lethargy, vomiting, loss of coordination, seizures and even liver failure.

Treatment: take your cat to the vet immediately.

Many sauces and soups could contain onion or garlic powder, while fat from meat can cause stomach ache and diarrhoea, and leftover bones can splinter and injure your cat's digestive system, or cause choking.

Symptoms: stomach problems are usually shown through vomiting and diarrhoea.

Treatment: seek veterinary care.

These can cause food poisoning from bacteria such as salmonella or E. coli, while raw egg whites can also affect vitamin B absorption (specifically biotin), causing skin problems. Raw fish likewise affects the absorption of vitamin B (this time thiamine), and can cause neurological problems and a coma if your cat eats it regularly.

Symptoms: if your cat is suffering from food poisoning, symptoms can include vomiting and diarrhoea, as well as excess saliva production.

Treatment: if your cat is an adult, and suffering from vomiting, then starve for 24 hours then put them on a bland diet of chicken or fish for two to three days. Remember to offer them water little and often for the first 24 hours, then leave the dish within easy reach thereafter. This should help the vomiting subside and get your cat feeling well again. If your cat is an adult and suffering from diarrhoea, then put them on a bland diet from the onset. If symptoms persist, consult a vet. If your cat is showing signs of losing coordination, such as falling over or developing a 'head tilt', then this could be a sign of vitamin B deficiency – in which case you must consult your vet immediately.

While it may seem the same as cat food, your dog's food doesn't contain the same blend of proteins and nutrients that your moggy needs to stay healthy and well-nourished.

Symptoms: malnourishment, which includes weight loss, tiredness, depression, weakness, dry skin, organ failure and even death.

Treatment: switch your pet's diet to a commercial cat food. If symptoms are severe, consult a vet.