My limited understanding of the history was that during the patent medicine era, medicines had proprietary formulas and varying compositions. For example, many formulas had cannabis extract, others contained opium. The initial regulations therefore were done for medical purposes of drug purity. Edited to add, it wouldn’t surprise me if the overuse of opium in the patent medicine era led directly to judging the medical usefulness of these drugs, although it’s just a guess.
My limited understanding of the history was that during the patent medicine era, medicines had proprietary formulas and varying compositions. For example, many formulas had cannabis extract, others contained opium. The initial regulations therefore were done for medical purposes of drug purity. Edited to add, it wouldn’t surprise me if the overuse of opium in the patent medicine era led directly to judging the medical usefulness of these drugs, although it’s just a guess.