They aren’t toxic or poisonous, but psilocybin does have a nauseating effect on many people. The cell walls of the mushrooms can be hard for some to digest as well, which is why many people make a tea or tinctures. You’d have to consume an absolutely insane dose of them — so much so that the current lethal dose isn’t known — for safety to be a concern at a toxicological level. Emotionally and mentally, different story.