Scientists have found that there are two major groups of serotonin receptors. Mushrooms acts on both classes, by blocking one while it stimulated the other. The serotonin group stimulated, serotonin 2, was found to be responsible for causing hallucinations. Mushrooms can be hard to identify and there are a number of different types of mushrooms that can induce the same type of hallucinations as do psilocybin mushrooms. However, many of them contain psychoactive compounds that can be extremely dangerous or lethal to the user.
Some species contain toxins that produce fatal damage to the liver and kidneys.