It is present in the leaves, skin, seeds and fruit of the avocado. Dogs and cats do not appear to be sensitive to this poison, although other animals certainly are. Ingestion of large amounts of persin might indeed bother a dogs stomach, but this would require eating a lot of leaves, bark or avocado peels. Although dogs are silly enough to eat the pits, not many dogs will sit down to graze on a meal of avocado leaves! Avocado Pulp