Hallucinogens are drugs that cause hallucinations, which is distortions in a person s perceptions of reality. Historically they were found in some plants and mushrooms and had been used mostly during religious rituals. Various hallucinogens came to be compounded chemically in the 20th century, and have spread among the young men in West European countries. Also in Japan, use of MDMA, or other hallucinogens is increasing in the young adult and minors. In recent years, Japanese medicine-related law were revised and most hallucinogens came to be treated as illegal drugs, but even now Japanese young men have got hallucinogens through the Internet and dance clubs, and medical and educational staffs and caregivers need to implement early intervention.