In the 1960s the major source of heroin was the Golden Triangle region of South East Asia. Until the 1970s opium was gathered here for shipment to Europe, where it was refined into heroin. This practice ensured that opium was the drug most readily available in SE Asia, and minimised the practice of injecting drug use. However, in the late 1970s heroin factories in Europe began to close down due to law enforcement, and it became safer to refine the drug at the site of production. Cheap heroin soon became easily available in SE Asia, and injecting drug use began to spread along heroin supply routes into Burma, Vietnam, Thailand, southern provinces of China and northern India as injectable quality heroin became more readily available and users developed tolerance to the smoked form of the drug.

New trends in the marketing of illicit drugs have had a major impact on the development of the epidemic. Organised crime syndicates moved into the heroin trade in the 1970s as it became clear that very large profits could be extracted from drug dealing. A flood of new heroin began to enter Europe and America following the fall of the Shah of Iran in 1979, leading to a further increase in heroin addiction. Heroin also begun to spread to African countries, especially Nigeria, as drug trafficking onto Europe and North America began increasingly using West Africa as a relay point.

The route of heroin smuggled into the West crosses through a number of Eastern European countries, and its path is marked by a high concentration of IVDUs, and a high HIV prevalence amongst this group even though the HIV epidemics are still young and have so far spared some cities and sub-populations.

The World Drug Report 2005 (UNODC) states that global illicit opium poppy cultivation increased by 16% in 2004 due entirely to increased cultivation in Afghanistan. Afghanistan is a high yield area (32kg/ha) and cultivation increased from 80,000 ha in 2003 to 131,000 ha in 2004 with every province now growing it. Despite this, global opium poppy cultivation is still less than it was in the early nineties. Declines were recorded in 2004 in Laos and Myanmar both low opium yield areas (13kg/ha). The main source of street heroin in the UK is the Golden Crescent countries of South West Asia, mainly Afghanistan, Iran and Pakistan. In June 2005 75% of Europe's and 95% of the UK’s heroin came from Afghanistan, with UK-based Turkish groups behind 70% of heroin in the UK (Druglink 2005).

The opium situation in Afghanistan as of August 2005 indicates a reduction in the cultivation of poppy by 21% (autumn 2005), however due to a good growing season the yield of opium by hectare increased from 32kg per hectare in 2004 to 39kg in 2005; as a result total potential production of opium decreased by only 2% (World Drug Report 2005, United Nations Office for drugs and crime).