Bay leaves are not poisonous. Bay leaves are difficult to eat due to bitterness and being pointy. They can also cause esophageal discomfort and injury if swallowed.
Bay leaves are generally left whole in recipes to avoid discomfort. It makes it easier to remove them from the food. Bay leaves have a very strong flavor and can overwhelm a dish. If the leaves are ground up or crushed, the leaves become more potent. Bay leaves can act as a repellent. Scattering bay leaves around the pantry will repel meal moths, flies, roaches, mice and silverfish. It is an active ingredient in killing jars. The vapors released will slowly kill the insects.