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Toxicities

A wide range of human foods, medications and other products can be dangerous to dogs and cats. The most common are as follows, but this is not an exhaustive list. Remember that almost all human medications can be toxic to animals, particularly at human-size doses.

Chocolate toxicity

Chocolate contains methylxanthines, chemicals which are similar to caffeine. Their toxicity results from exciting the nervous system. The first sign you may see of toxicity is hyperexcitability. This may progress to increased heart rate and temperature, and in severe cases, seizures. Gastrointestinal effects (vomiting and diarrhoea) may also be seen.

Onion toxicity

A chemical present in onions and other members of the onion family (such as garlic and leek) destroys red blood cells in dogs. At low doses, this just results in lethargy, but at high doses it can cause life-threatening anaemia.

Grape / raisin toxicity

An unknown chemical present in grapes, raisins and sultanas can cause damage to the kidneys in dogs. Some dogs are more susceptible than others – there have been cases where a single grape has caused toxicity, whilst some dogs can eat a whole bunch and show no signs. Signs of toxicity include vomiting, diarrhoea, lethargy and abdominal pain. Err on the side of caution and avoid feeding them!

Snail bait toxicity

There are two types of snail bait – metaldehyde, which is green, and carbamate, which is blue. Their mechanisms of toxicity are different but both can cause tremors, vomiting and seizures, and can be rapidly fatal if left untreated.

Rat bait toxicity

The active compound in rodenticides stops the body from using vitamin K. Since vitamin K is required for the body to make clotting factors that allow the body to produce blood clots, rodenticides can lead to a 'coagulopathy', or a bleeding tendency, about 72 hours after ingestion.

Lily toxicity

An unknown chemical in all parts of all species of lily is very toxic to cats. Ingestion of even a tiny amount can cause fatal kidney failure.

Paracetamol toxicity

Paracetamol is highly toxic to cats, but can also cause toxicity in dogs at higher doses. A metabolite of paracetamol damages red blood cells, rapidly leading to severe anaemia. If the animal survives, delayed toxicity to the liver can also occur.

Anti-inflammatory toxicity

Non-steroidal anti-inflammatory drugs such as Nurofen and Voltaren can be very toxic to the kidneys of both dogs and cats, even at low doses. In some animals they may also affect the liver and clotting function.

Macadamia nut toxicity

Macadamia nuts can cause muscular weakness, joint pain and neurological signs in dogs via an unknown mechanism. They are not known to cause toxicity in cats.

Ethylene glycol (anti-freeze) toxicity

Ethylene glycol causes toxicity in three stages as the chemical is metabolised in the body:

  • Stage 1 – Depression, incoordination, possibly seizures
  • Stage 2 – Increased heart and respiratory rate
  • Stage 3 – Acute kidney failure – vomiting, refusal to eat, severe depression

Ethylene glycol toxicity is frequently irreversible but chances of success are greater if it is identified and treated as soon as possible.

Other common household products that can cause toxicity to the gastrointestinal tract include fertilisers and detergents.

If you think your pet may have ingested a toxic product, contact your vet immediately to see if there is anything you can do at home to help. Usually the best thing to do is to bring your pet to the vet immediately. We will first examine your pet and stabilise it if this is required. This may involve IV fluids, oxygen and/or active cooling if your pet has overheated. The next aim of treatment is decontamination – to remove as much of the toxin as possible from your pet's body. To do this we may induce vomiting, administer activated charcoal and/or anaesthetise your pet to flush out the stomach and rectum. From here treatment is usually supportive until your pet recovers. Some toxins have specific antidotes, but the majority do not.