The FDA has been overseeing drugs in the US since the beginning of the 20th century. In 1970 the FDA released the following drug classifications, or drug schedules, under the Controlled Substance Act (CSA). The drug classificaton schedules organize drugs into groups based on risk of abuse or harm. Those drugs with high risk and no counterbalancing benefit are banned from medical practice and are Schedule I drugs.
Substances in this schedule have no currently accepted medical use in the United States, a lack of accepted safety for use under medical supervision, and a high potential for abuse.
Some examples of substances listed in Schedule I are:
Information provided above is courtesy of: https://www.dea.gov