There are certain types of avocado that are known to be poisonous due to the amount of persin in the avocado leaves, seeds, bark, and fruit. Studies have been conducted that show that avocado is not highly toxic to dogs; however, if a dog were to ingest the large seed (pit) of an avocado, it could cause illness. Avocado pits can cause blockages within the gastrointestinal tract and different varieties of avocado have varying amounts of persin. Avocado is highly toxic to horses, goats, birds, and cattle, and with dogs, depending on the amount they consume, can cause an upset stomach. The most toxic portion of an avocado is the leaf.

Avocado poisoning in dogs occurs when dogs ingest the pit of an avocado. The avocado pit contains a poisonous substance called persin, and, when ingested, can cause dogs to become ill. The avocado is potentially toxic, with the leaf being of most danger.

Avocado is not highly toxic to dogs; however, after consuming parts of an avocado your dog may develop specific symptoms. Symptoms can include:

Illness from eating an avocado may be confused with other conditions, especially if there is no evidence of avocado consumption. Differential diagnoses are:

The cause of illness from ingesting avocado comes from the dog consuming the fruit, pit, stem or the leaves. Canines are thought to be relatively resistant to the poisonous effects of avocado, though there have been a few cases of toxicity documented. The consumption of large amounts will cause gastrointestinal irritation, and the pit of the avocado presents a danger due to the size, which can lead to an obstruction if swallowed. 

If you know that your dog has consumed a large amount of avocado or the pit, call your veterinarian. Once you get to the veterinarian, he will check your dog for any clinical signs of distress and do a physical examination. The veterinarian may choose to do a urinalysis, blood work, and biochemistry profile, simply to check your dog’s system and to rule out any underling medical issues.

A definitive diagnosis of avocado poisoning is made by the veterinarian by looking at your dog’s symptoms and having knowledge of exposure and consumption of avocado. 

If your dog has ingested the pit, the vet may perform an abdominal scan or contrast x-ray to assess for a blockage.

Since the degree of toxicity of avocados to dogs is quite debatable, the veterinarian will be the one to make the expert decisions concerning treatment. If the dog has ingested the avocado pit and it is lodged in his upper GI tract, the veterinarian will need to use an endoscope to locate the pit and remove it. If the pit is lower down, an abdominal surgery will be performed.

As for side effects from the persin, treatment methods may include:

Treatment will depend on the signs and may include an anti-nausea injection, intravenous fluids and ant-acids.

Prognosis is considered good in many cases of avocado consumption. Once your dog is treated, he will more than likely recover just fine. In terms of a blockage in the gastrointestinal tract from the pit, this depends on the severity of blockage and the recovery from surgery to remove the pit. It is important to follow your veterinarian’s instructions for at-home recovery. The veterinarian will explain to you how to administer any analgesics or other medications, and will let you know of any side effects from these drugs. If any new symptoms occur or if you have any questions, it is important to contact the physician.