People who inject opium feel a rush of pleasure, followed by a dreamy, pleasant state in which they have little sensitivity to pain. Opium is obtained by slightly incising the seed capsules of the poppy after the plant's flower petals have fallen. The slit seedpods exude a milky latex that coagulates and changes colour, turning into a gumlike brown mass upon exposure to air. This raw opium may be ground into a powder, sold as lumps, cakes, or bricks, or treated further to obtain such derivatives as morphine, codeine, and heroin.
Opiates exert their main effects on the brain and spinal cord.
Their principal action is to relieve or suppress pain. Immediately after injection, the feelings are most intense. This feeling is described as similar to a sexual orgasm. These are among the neurotransmittors that control movement, moods, and physiology. The pharmacologically active principles of opium reside in its alkaloids, the most important of which, morphine, constitutes about 10 percent by weight of raw opium.