The moulds that spoil food and grow in composting piles can sometimes produce dangerous toxins. Dogs that eat these may become very ill. Never give mouldy food to your dog. Speak to a vet straight away if you think your dog has eaten spoiled food or anything from a composting pile.    

There are two main types of dangerous toxins that moulds can produce. The most common are tremorgenic toxins. These cause uncontrolled shaking and trembling. In severe cases, they may cause seizures or heat stroke. However, most dogs fully recover if they receive immediate treatment. The other type is aflatoxins, which cause liver damage. The symptoms may take several days to appear, but recovery is more difficult, and sadly, many dogs don’t survive. In both cases, treatment should be started as soon as possible to improve the chances of a full recovery.

What causes mouldy food poisoning in dogs? 

Tremorgenic toxins

• Sometimes produced by mould that grows on bread and cereal products, dairy products, nuts and other spoiled foods.

• The amount of toxin produced varies greatly with mould strain and environmental conditions, so it’s hard to know when dangerous levels may be present.

• The toxins are quickly absorbed from the stomach and gut, and symptoms can start in an hour or less.

• These toxins can get into the brain, which is where most of the symptoms are thought to come from.

• Uncontrolled shaking and trembling are the main symptoms, but in severe cases, this can lead to life-threatening hyperthermia (heat stroke) or seizures.

Aflatoxins

• Aflatoxins may be produced when food isn’t properly preserved.

• Cases are rare, but errors or accidents during the industrial production of dog food can sometimes cause outbreaks.

• These toxins can also be produced in foods that haven’t been stored properly.

• Symptoms may take several days or weeks to develop.

• Liver damage is the main consequence of ingesting these toxins and is often severe.

Symptoms of mouldy food poisoning in dogs

The symptoms will depend on the type of toxin ingested.

Tremorgenic toxins:

• Vomiting

• Uncontrolled shaking and trembling, often continuous and affecting the whole body

• Panting

• Restlessness

• Exaggerated reactions to noises, touch and movement; these can sometimes worsen the tremors 

• Incoordination

• Raised body temperature, possibly leading to hyperthermia or heat stroke

• Seizures

• Coma

Aflatoxins:

Symptoms may develop in just a few days or over several weeks

• May unexpectedly refuse a specific food

• Vomiting

• Diarrhoea

• Jaundice (yellow gums and eyes)

• Excessive bruising or bleeding

• Black, tarry stools

• Poor appetite

• Fluid build-up in the belly (ascites)

• Liver failure

Dogs at higher risk of mouldy food poisoning

• Intoxication can affect dogs of any age, but younger dogs are more likely to eat inappropriate things

• Small amounts of toxin are enough to cause illness in very small dogs

• Scavenging or unsupervised outdoor roaming increases the risk of exposure

How do vets diagnose mouldy food poisoning in dogs?

• In many cases, the ingestion of mouldy food will be seen, or the mouldy food will be present in the vomit.

• For tremorgenic toxins, the typical symptoms of sudden uncontrolled trembling may indicate an intoxication, although other common toxins cause similar symptoms (slug poison, insecticides, herbicides, chocolate, caffeine, strychnine, recreational drugs).

• For aflatoxins, general blood tests may show liver damage and coagulation problems, but determining the cause can be difficult if the ingestion of mouldy food was not seen.

• In both cases, specialist lab tests may be able to detect the toxins in samples of vomit or contaminated food.

• In animals that do not survive, samples for diagnosis may be obtained during post-mortem examination.

Veterinary treatment of mouldy food poisoning in dogs

• The first and most important step in treating intoxication is stopping the poison from entering the blood and organs. If mouldy food ingestion is suspected, take your dog to a vet immediately so the stomach can be emptied as quickly as possible, ideally within 30 minutes. Your vet will do this safely with an injection or by pumping the stomach under anaesthesia. 

• Tremorgenic toxins:

  • If tremors develop, the pet will need to be hospitalised and receive medications to control them. 

  • Medications used may be similar to anti-epileptic medications, like diazepam, phenobarbital or midazolam. A specific anti-tremor medication called methocarbamol is often also used.

  • Other treatments may also be needed to manage symptoms and prevent dehydration.

  • Body temperature will need to be monitored closely, and body cooling treatments may be needed if it gets dangerously high.

• Aflatoxin:

  • Intensive supportive care is often required.

  • Whole blood or plasma transfusion may be needed to replenish coagulation factors, red blood cells and platelets. Vitamin K may need to be administered by injection.

  • Symptomatic treatment may be needed for vomiting and other digestive symptoms.

  • Medications to protect the liver may be administered, such as N-acetylcysteine or S-adenosylmethionine (SAMe).

Home treatment of mouldy food poisoning in dogs

• Always contact a vet for advice immediately if you think your pet has ingested mouldy food. If the amount ingested is concerning, immediate decontamination treatment is the best option.

Prevention of mouldy food poisoning in dogs

• Do not feed your dog any food that visibly contains mould, or that seems spoiled (abnormal smell, consistency, appearance).

• Make sure all bins are secure, and your dog can’t get into them, especially those containing food leftovers or discarded food.

• Do not leave your dog unattended around compost. 

• Monitor your dog closely during walks and prevent access to rubbish or discarded food.

Living with mouldy food poisoning in dogs

• Most dogs recover fully from tremorgenic toxins within 24-48 hours, although some cases may take longer. Lingering effects are extremely rare.

• Aflatoxin intoxication is usually severe, and many dogs don’t survive. When they do, they may be left with chronic liver disease. Such cases will require lifelong monitoring and may benefit from preventive treatments and special diets.

When to worry about mouldy food poisoning in dogs

Always speak to a vet immediately if you suspect your dog has ingested mouldy food, so the risk can be assessed and treatment advice given. If your dog develops any of the following symptoms, see a vet as soon as possible:

• Severe vomiting or drooling

• Constant shaking or trembling

• Wobbliness or seizures

• Weakness or collapse

• Excessive panting or trouble breathing

• Excessive drinking and urination

• Bleeding

Safe treats for dogs