Chasing the Dragon Ya Ba. 70 Rai, Bangkok 2007. 10. Nikon FM2, 24mm(2.0), Tri-X "Chasing the dragon" (a slang phrase of Cantonese origin from Hong Kong) refers to inhaling the smoke from heated morphine or heroin. (Opium is referred to as a dragon in Asian cultures.) The term evokes the similarity between the rippling smoke and a dragon's tail. Opium use was common throughout the Western world in colonial times, when Chinese were kept as slaves. The global presence of slavery caused a demand for opium that was filled by Western traders complicit with slave owners, as it kept the slaves mellow and eased the pain (and complaint) from hard labor[citation needed]. Opium dens consequently became common in Western trading ports during the period. In modern times, with the advent of heroin, the method traveled from China to Europe again, where, during the early 1990s, the technique spread to the Netherlands, and from there throughout the world. The most common form of smoked heroin is heroin base, which is also known as "number 3 heroin", so called because it forgoes the final steps to make the heroin into the salt heroin hydrochloride (see Heroin). "Chasing the dragon" may be "safer" (safer being a relative term) than injecting heroin due to the risk of infection from needle sharing, as well as the stress that injecting puts on veins. The technique also avoids the delivery of heroin into the bloodstream instantaneously, as is the case with injection, a fact which many say reduces one's chances of accidentally overdosing. A small puff can be inhaled as a method of gauging the strength of the heroin. Also, the lungs can act to filter out additional pollutants that otherwise would pass directly into the bloodstream; however, in any case it is never harmless to expose the lungs to any kind of smoke. Inhaling heroin, however, may lead to Toxic leukoencephalopathy. "Chasing the dragon" may be accomplished by placing opium or cupping heroin powder in smooth aluminum foil and gently heating from below with a flame, then inhaling the resulting smoke. The foil heats to more than 600 degrees Celsius in 2 seconds[citation needed]. Several types of aluminum foil are coated with a thin plastic film, and it is recommended that this film first be melted away, then wiped clean from the foil, as plastic produces harmful fumes when melted and inhaled. Smoke from opiates cause the passages in the lungs to constrict, on top of their effect of depressing breathing. Individuals with any form of breathing difficulty ( including asthma) should avoid smoking altogether; there have been deaths in the Netherlands resulting from individuals with asthma suffocating due to inhaling heroin smoke. From Wikipedia