The “magic” ingredient in hallucinogenic mushrooms is psilocybin, a compound that breaks down into psilocin in the body.
Psilocin bonds to serotonin receptors all over the brain, and can cause hallucinations as well as synesthesia, or the mixture of two senses.
Under the influence, for example, a person might feel that they can smell colors.
In keeping with the human tradition of eating anything that might alter your mind, people have been ingesting psilocybin-continuing mushrooms for thousands of years.
Synthetic psilocybin is now under study as a potential treatment for anxiety, depression and addiction.