The avocado is loved for its vitamin-D and fatty acid-rich pulp, but its pit is usually discarded and viewed not only as inedible, but also as poisonous, especially to domestic animals.
The pit does in fact contain a fungicidal toxin called persin. Eaten in large quantities, persin can be harmful, but it’s very unlikely humans or domestic animals would eat enough avocado pits to do damage.
A more common problem pet owners face with avocado pits is whole-pit ingestion, because the pit is large enough to cause an obstruction in your pet’s digestive track. According Dr. Whitehead, a veterinarian on JustAnswer, if this happens you should induce vomiting as soon as possible. If you’re queasy about inducing vomiting, have your pet seen by an emergency vet as soon as you realize what has happened.
But still, the pits do contain a toxin, so wouldn’t that make them poisonous on some level? Dr. Deb, another veterinarian on JustAnswer, sets the rumors straight:
“There are other species which are more susceptible to avocados since they contain persin and they tend to be more reactive to this ingredient. Horses, cattle, goats, and birds, in particular, can become quite ill (or even die) if any part of an avocado is ingested.
Rumors to the contrary, ingestion of avocados by a dog (or cat for that matter) will not cause serious side effects.”
Dr. Deb delivers the final verdict: False. Avocado pits aren’t poisonous to humans and domestic animals. In fact for humans, avocado pits are actually nutritious. They’re rich in anti-oxidants and soluble fiber.