Avocado is documented to be harmful to some animals; such as cats, dogs, cattle, goats, rabbits, rats, guinea pigs, birds, fish, and horses can be severely harmed or even killed when they consume them. The avocado fruit is poisonous to some birds, and the American Society for the Prevention of Cruelty to Animals (ASPCA) lists it as toxic to many animals including cats, dogs, and horses. Therefore keep way Avocado and Avocado Oil products from your pets.

Avocado leaves contain a toxic fatty acid derivative, persin, which in sufficient quantity can cause colic in horses and, without veterinary treatment, may cause even death to the animal. The symptoms include gastrointestinal irritation, vomiting, diarrhea, respiratory distress, congestion, fluid accumulation around the tissues of the heart, and even death.

Birds also seem to be particularly sensitive to this toxic compound.