Beware of common cat poisoning

By far the highest numbers of poisonings seen in cats are due to well meaning owners either dosing their cats with human medications or using natural remedies. Below is some information on some of the more common or seemingly innocuous sources.



Paracetamol, even in tiny doses can be lethal to cats. Cats do not have the enzymes to metabolise Paracetamol safely, so even the smallest dose will cause toxic levels. It causes the breakdown of red blood cells creating a condition called methaemaglobinaemia and liver damage. This is sadly invariably fatal. If your cat ingests any amount of Paracetamol, seek immediate veterinary attention, as there is an antidote called Acetylcysteine which can be effective if administered early enough.

Tea Tree Oil

Tea Tree Oil if taken orally is toxic to cats (as well as dogs and humans). The concentrated oils are also rapidly absorbed through the skin. Minor symptoms like drooling or vomiting may be found with mild doses of oil. Animals with moderate illness may appear weak, or partially paralyzed. Severely ill animals have life threatening symptoms like tremors, seizures, reduced level of consciousness or, coma. Symptoms follow 2 – 12 hours after exposure. Topical application of concentrated oil can result in the same toxicity as accidental oral ingestion. Given the tendency of pets to groom, especially cats, the toxicity risk of topical applications is very high.


Xylitol is increasingly found as a sugar substitute in many “diet” foods, and is perfectly safe for human consumption. Cats (and dogs) have a very different metabolism to humans and the ingestion of Xylitol, even in very small amounts can be very dangerous. It induces a massive release of Insulin into the bloodstream, causing hypoglycaemia (low blood sugar). This results in lethargy and even coma. In larger doses, irreversible liver failure inevitably occurs, generally resulting in death.

Onions and Garlic

Onions and garlic contain an ingredient called thiosulphate which is toxic to cats and dogs. Garlic tends to be more toxic than onions on an ounce for ounce basis, and cooking does not destroy the toxin. While it’s uncommon for cats to eat enough raw onion and garlic to cause serious problems, exposure to concentrated forms of onion or garlic, such as dehydrated onions, onion soup mix or garlic powder, could put cats at risk of toxicosis. The ingestion of onions causes a condition called haemolytic anaemia, which is characterised by damage to the red blood cells. Onion toxicity can cause the red blood cells circulating through your pet’s body to burst. Symptoms of this condition include breathlessness, lethargy, diarrhoea and vomiting. It may take up to 2 to 4 days after your pet eats the onion for symptoms to appear.

Please do not believe everything that is published on the internet. While there are some very useful articles, some do contain misguided and potentially harmful advice.
Unless a medication or supplement has been prescribed by your veterinarian, contact him/her first to ensure its safety in cats.

By Sr Janice Clover
Hayfields Veterinary Clinic

Registrar's Office

  P O Box 28732, Kensington, Gauteng
  011 616 7017
  086 616 8294


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