The article discusses the history and current guidelines for the safe administration of classical hallucinogens (psychedelics) in human research. It highlights the unique psychological risks associated with hallucinogen use, such as "bad trips" and prolonged psychosis, and outlines safeguards to minimize these risks. The paper emphasizes the importance of careful volunteer selection, thorough preparation, and the presence of trained monitors during sessions. It also notes that while hallucinogens are generally safe physiologically, they can cause significant psychological distress. The guidelines include exclusion of volunteers with a history of psychiatric disorders, ensuring a safe and supportive environment, and providing interpersonal support during sessions. The paper also addresses the potential for hallucinogen persisting perception disorder (HPPD) and the need for follow-up assessments. Overall, the study underscores the importance of rigorous safety protocols to ensure the well-being of participants and the validity of research findings.The article discusses the history and current guidelines for the safe administration of classical hallucinogens (psychedelics) in human research. It highlights the unique psychological risks associated with hallucinogen use, such as "bad trips" and prolonged psychosis, and outlines safeguards to minimize these risks. The paper emphasizes the importance of careful volunteer selection, thorough preparation, and the presence of trained monitors during sessions. It also notes that while hallucinogens are generally safe physiologically, they can cause significant psychological distress. The guidelines include exclusion of volunteers with a history of psychiatric disorders, ensuring a safe and supportive environment, and providing interpersonal support during sessions. The paper also addresses the potential for hallucinogen persisting perception disorder (HPPD) and the need for follow-up assessments. Overall, the study underscores the importance of rigorous safety protocols to ensure the well-being of participants and the validity of research findings.