Opium has been produced and consumed since the nineteenth century in the areas of Asia currently referred to as the Golden Crescent and the Golden Triangle. In the 1970s and 1980s, most countries from Afghanistan to Japan experienced a heroin epidemic of varying degrees of severity. Opium and heroin abuse appeared to be more severe in countries and areas where those drugs were produced, an exception being Hong Kong, which has had a large population of heroin abusers for more than two decades. Drug injecting was far more common in countries of the Golden Triangle than in those of the Golden Crescent. In Myanmar and Thailand, for example, up to 90 per cent of chronic heroin abusers practised intravenous injection, which appeared to spread to heroin abusers in nearby territories such as the State of Manipur in India. Yunnan province in China, as well as Malaysia and Viet Nam. Amphetamine abuse was more frequent in Japan and the Republic of Korea for a number of years, while illicit production and consumption in the Philippines have recently shown significant increases. The injection of amphetamines was common only in the Republic of Korea. The prevalence of injecting among institutionalized methamphetamine abusers was reported at about 90 per cent. Most countries in Asia first reported cases of infection with the human immunodeficiency virus (HIV) in the mid-1980s. An extremely rapid spead of the epidemic and high prevalence, at rates of from 30 to 90 per cent, of HIV infection among the sample of intravenous heroin abusers were observed in a few countries with a high prevalence of intravenous injecting, such as India (in the State of Manipur), Myanmar and Thailand. The rest had either few reported cases or none at all, even though needle-sharing was found to be common. Great caution should be exercised in interpreting prevalence because of vast differences in methods of assessment. Given the vulnerability of intravenous drug abusers to rapid transmission of HIV infection, the prevention of drug injecting is of paramount importance in arresting the spread of the epidemic. Efforts to contain drug abuse, though difficult, are a principal means of achieving that end.