Human foods to avoid for cats

There are a number of human foods that you should avoid feeding to cats as they can have an adverse effect on their health.


Consumption of alcoholic beverages and food products containing alcohol can cause:

  • vomiting
  • diarrhoea
  • decreased coordination
  • difficulty breathing
  • tremors
  • coma
  • death.


Chocolate contains theobromine (a methlyzanthine) and caffeine which are toxic to cats. Toxicity is dose related meaning that the overall effect of chocolate ingestions depends on the size of the cat, the amount eaten and the type of chocolate.

Symptoms include:

  • restlessness
  • excitement
  • hyperactivity
  • nervousness
  • trembling
  • vomiting
  • diarrhoea
  • increased drinking and urination
  • increased heart rate
  • seizures.

Note that darker chocolate is more dangerous than milk chocolate. White chocolate has the lowest level of methylxanthines, while baking chocolate contains the highest.

Coffee or caffeine products (including tea)

In large enough doses, caffeine can be fatal for a cat and there is no antidote. Symptoms of caffeine poisoning include:

  • restlessness
  • rapid breathing
  • abnormal heart rhythms
  • elevated body temperature
  • muscle tremors
  • seizures
  • collapse.

Cooked bones

Cooked bones can splinter and cause gastrointestinal obstruction or laceration.

Fat trimmings

Fat, both cooked and uncooked, can cause intestinal upset, with vomiting and diarrhoea. It can also lead to your pet to developing pancreatitis.

Grapes, raisins, sultanas and currants

The toxic substance within grapes and raisins is unknown, but even a small amount of ingestion can lead to kidney failure.

Milk and dairy

Adult cats do not possess significant amounts of lactase (the enzyme that breaks down lactose in milk), so milk and other dairy based products can cause diarrhoea or other digestive upset.

Onions, potato, garlic, leeks and chives

These contain a substance that can cause red blood cell damage leading to anaemia and gastrointestinal irritation. Toxic doses of colic can cause:

  • pale gums
  • increased heart rate
  • increased respiratory rate
  • collapse.

Garlic is considered to be about 5 times as potent as onion and leeks.


Large amounts of salt can produce excessive thirst and urination, or even sodium ion poisoning.

Signs that your cat may have eaten too many salty foods include:

  • depression
  • tremors
  • elevated body temperature
  • seizures.


Tomatoes contain a substance that causes violent gastro-intestinal problems. Signs include:

  • excessive drooling
  • inappetence
  • depression
  • weaknesses
  • dilated pupils
  • slow heart rate.

Ripe fruit is non-toxic.

Yeast dough

Yeast dough can rise and cause gas to accumulate in your cat's digestive system. This can be painful and cause the stomach or intestines to rupture. The risk diminishes after the dough is cooked and the yeast has fully risen.


The information on this page was gathered from the ASPCA website, the RSPCA knowledge base, the Purina website and the Cornell University – Department of Animal Science website.

Page last updated: 09 Dec 2020