Laudanum Concentrated (Deodorized and Denarcotized) "Four times the strength of tincture, Used when Tinct. Opii U.S.P. is contraindicated" for $9.50 per pint, and (4) Opium (Aqueous), U.S.P., 1890, "Tr. (assayed) Papayer Somniferum" for $2.25 per pint. In 1929–30, Parke, Davis & Co., a major US drug manufacturer based in Detroit, Michigan, sold "Opium, U.S.P. (Laudanum)", as Tincture No. 23, for $10.80 per pint (16 fluid ounces), and "Opium Camphorated, U.S.P. (Paregoric)", as Tincture No. 20, for $2.20 per pint. Concentrated versions were available. "Opium Camphorated, for U.S.P. Tincture: Liquid No. 338" was "exactly 8 "times the strength of Tincture Opium Camphorated
Laudanum other such drugs continued to be legally available without prescription as long as they were labeled. It is estimated that sale of patent medicines containing opiates decreased by 33% after labeling was mandated. In 1906 in Britain and in 1908 in Canada "laws requiring disclosure of ingredients and limitation of narcotic content were instituted". The Harrison Narcotics Tax Act of 1914 restricted the manufacture and distribution of opiates, including laudanum, and coca derivatives in the US. This was followed by France's "" in 1916, and Britain's Dangerous Drugs Act in 1920. Laudanum was supplied to druggists and physicians in regular