Hallucinogens are a varied class of compounds with different chemical compositions and mechanisms of action. Despite these differences, they are often grouped together for their shared ability to create relatively consistent effects on a person’s sensation, perception, mood, or cognition. Hallucinogen use disorder (HUD) is one of the least common substance use disorders; however, rates of hallucinogen use and HUD are rising. Due to the diverse nature of these compounds, lack of funding, and overall low incidence of HUD, several barriers are contributing to an extreme lack of research on HUD. This paucity of studies has contributed to a limited understanding of the risks involved in the development of HUD, the neurobiology unique to HUD, or treatments for HUD. In general, hallucinogens are relatively safe when used by healthy individuals in comparison to other scheduled drugs, but there are still risks in developing problematic use or exacerbating other medical or psychiatric conditions. With rising interest in the therapeutic potentials of hallucinogens for other psychiatric or substance use disorders, the mounting attention by the media and researchers alike may help shine more light on hallucinogen use disorders.