Period illustration of Chinese opium smokers in San Francisco. Opium is a narcotic drug obtained from the seeds of the opium poppy. It contains the chemicals morphine and codeine, as well as other alkaloids. The opium resin from the poppy is processed, and then burned in pipes. The smoker inhales the vapours from the burning resin. Opium is an addictive drug. In the 19th century and the early 20th century, opium smoking was common worldwide, especially in Asia, which was one of the sources of the opium poppy. There were many opium dens where such smoking took place.