However, early efforts to isolate an active alkaloid were unsuccessful.[3] It is described and standardized in the 1898 United States Pharmacopoeia[4] and 1911 British Pharmaceutical Codex[5] for use in lozenges, tinctures, and syrups as a sedative for irritable cough or as a mild hypnotic (sleeping aid) for insomnia. The standard definition of lactucarium in these codices required its production from Lactuca virosa, but it was recognized that smaller quantities of lactucarium could be produced in a similar way from Lactuca sativa and Lactuca canadensis var. elongata, and even that lettuce-opium obtained from Lactuca serriola or Lactuca quercina was of superior quality.[6]