Laudanum his "archanum" or "laudanum", may or may not have contained opium. Paracelsus' laudanum was strikingly different from the standard laudanum of the 17th century and beyond, containing crushed pearls, musk, amber, and other substances. One researcher has documented that "Laudanum, as listed in the "London Pharmacopoeia" (1618), was a pill made from opium, saffron, castor, ambergris, musk and nutmeg". Laudanum remained largely unknown until the 1660s when English physician Thomas Sydenham (1624–1689) compounded a proprietary opium tincture that he also named laudanum, although it differed substantially from the laudanum of Paracelsus. In 1676 Sydenham published a seminal work, "Medical Observations
Laudanum most common contemporary formulation), among others. Depending on the version, additional amounts of the substances and additional active ingredients (e.g. saffron, sugar, eugenol) are added, modifying its effects (e.g., amount of sedation, or anti-tussive properties). There is probably no single reference that lists all the pharmaceutical variations of laudanum that were created and used in different countries during centuries since it was initially formulated. The reasons are that in addition to official variations described in pharmacoepias, pharmacists and drug manufacturers were free to alter such formulas. The alcohol content of Laudanum probably varied substantially; on the labels of turn-of-the-century bottles