The Columbia Encyclopedia, Sixth Edition. Columbia Encyclopedia World Factbook American Heritage Coll.
Opium varies in color from yellow to dark brown and has a characteristic odor and a bitter taste.
Its chief active principle is the alkaloid morphine , a narcotic . 1 Effects and Addictive Nature Opium and its various constituents exert effects upon the body ranging from analgesia, or insensitivity to pain, to narcosis, or depressed physiological activity leading to stupor. Opium users describe experiencing a feeling of calm and well-being. Opium addicts in otherwise good physical and mental health whose drug needs are met are thought to experience no debilitating physiological effects from their addiction, although there is some evidence that immune function is compromised. However, their preoccupation with the drug and its acquisition can lead to malnutrition and general poor self-care and an increased risk of disease.