During Prohibition (1920-1933), the Volstead Act outlawed the production, sale, and distribution of alcohol in the U.S., but there was a legal loophole: medicinal spirits. Doctors were allowed to prescribe alcohol for medical purposes, and this led to a surge in demand for "medicinal alcohol.”

The Volstead Act included a clause that permitted doctors to prescribe alcohol for medicinal purposes.  Patients could take their prescriptions to licensed pharmacies, which could legally dispense whiskey.  The alcohol had to be bottled and labeled with medicinal branding, often stating: "For Medicinal Use Only. Sale or use for other purposes will cause heavy penalties.“