Food toxicities in dogs and cats

If you suspect your pet has ingested a toxin, call the Australian Animal Poisons Helpline on
1300 869 738 or your local vet (e.g. HomeVetBondi 0433 533 037).

Everybody likes to spoil their pet with treats from time to time. However, when it comes to  sharing your own food with your pet, you need to be very careful as some human foods can be toxic to dogs and cats. Below are some of the more common foods that can be poisonous when fed to dogs and cats. Bear in mind, this is not a complete list and the safest treats to give are always those made specially for pets.

Chocolate

As well as caffeine, chocolate contains another similar chemical called theobromine. Dogs and cats can’t metabolise theobromine or caffeine as well as we can, which means toxic levels can build up in their bloodstream very quickly. When toxic levels are reached, dogs and cats may exhibit vomiting, diarrhoea, panting, hyperactivity, excessive urination and, in severe cases, muscle tremors and seizures. Prompt treatment is extremely important and should be sought asap, ideally before signs of toxicity develop. Treatment includes inducing the animal to vomit and lavaging the stomach with charcoal to reduce toxin absorption, intravenous fluids, and specific medications if muscle tremors or seizures are present.

So how much chocolate is too much? Dark chocolate and cooking chocolate contain much more theobromine and caffeine than milk chocolate and so much smaller quantities are needed to make an animal sick, whereas white chocolate only has very low levels and therefore needs to be ingested in much larger quantities for toxicity to develop. If your pet has ingested chocolate, you can use an online calculator, such as the MSD Veterinary Manual Chocolate Toxicity calculator to find out if they need emergency treatment. NB: These calculators should be used as a guide only - always contact your vet for advice if you are in any doubt whether your dog or cat has ingested a toxic amount of chocolate.

Grapes

Foods containing grapes (including raisins) or currants should never be fed to your dog or cat. While vets don’t yet understand the exact mechanism, these fruits can cause acute kidney failure which can be life threatening and, even if successfully treated, can lead to life-long health problems. The earliest signs of grape/currant toxicity (usually seen within 24 hours) are vomiting, inappetance, lethargy and sometimes diarrhoea.

Not every dog or cat will be affected if they consume grapes/currants and the amount needed to induce toxicity can vary greatly from animal to animal. If you suspect your pet has ingested any amount of grapes/currants, take them to see a vet straight away. Do not wait for them to show signs of being unwell. Treatment involves inducing vomiting, lavaging the stomach with charcoal, and intravenous fluid therapy.

Avocado

Avocados contain a chemical called persin, which is found in much higher concentrations in unripe avocados. Persin can lead to vomiting and diarrhoea and so, while serious cases of poisonings are rare, avocados should not be fed as a treat to your pet. 

Onion and garlic

Onion, garlic, chives and leeks are all from the same family (Allium) and all contain disulfides and thiosulphates which can be toxic to dogs and cats. Regardless of whether they are cooked, raw or dehydrated, these foods should never be fed to your pet. Poisoning can range from mild vomiting and diarrhoea to a life-threatening anaemia (called haemolytic anaemia) caused by destruction of the red blood cells. The anaemia can take several days to develop. With this particular group of foods, cats are more susceptible to toxicity than dogs. If you believe your dog or cat has ingested any food from the onion family, call your vet straight away.

Xylitol

Xylitol is a sweetener/sugar substitute found commonly in some chewing gums and toothpastes. It can also be found in certain foods and nutritional supplements. While its danger to cats is debatable, we know xylitol is toxic to dogs as it causes a spike in insulin and a subsequent severe drop in blood glucose. Low blood glucose (i.e. hypoglycaemia) can occur within 30 minutes of ingestion and can cause weakness, incoordination, disorientation and, if very severe, seizures and coma. Xylitol poisoning can also lead to irreversible liver damage.

For more information on pet toxicities, visit the Australian Animal Poisons Helpline website.