The milky juice derived from the un-ripe seed capsules of the poppy plant Papaver somniferum is called opium. This material, which dries to a brownish gum contains a large number of alkaloid compounds. These ALKALOIDS can be categorized into two major groups—the benzylisoquinolines and the phenanthrenes. The phenanthrene group includes the OPIOIDS, the most important of which is MORPHINE, which constitutes approximately 10 percent of opium. CODEINE is present in far smaller quantities, at 0.5 percent, and thebaine is only 0.2 percent. Both morphine and codeine can be extracted from opium and each crystallized to yield pure compounds. Virtually all morphine is derived from opium, since to synthesize it is complex and expensive. Although morphine and codeine have been used extensively in the clinical treatment of PAIN, thebaine is equally important—it is the starting material for the synthesis of many semi-synthetic opioid analgesics (painkillers). Of these, the most widely...