Opium. Coloured scanning electron micrograph (SEM) of opium resin. Opium is a narcotic drug obtained from the unripe seed pods of the opium poppy (Papaver somniferum). When the seed pods are cut a white milky latex is released which dries to a solid resin. Opium contains the potent analgesics (painkillers) morphine and codeine, and is used to treat severe pain. Heroin is also derived from opium. All of these substances are highly addictive after only a short period of use. The body also develops tolerance to the drugs quickly and larger doses are needed to achieve the same effect.