The unregulated supply of AIDS drugs in the non-industrialised world threatens to accelerate the development of drug-resistant HIV strains. That is the conclusion of a study from the London School of Hygiene and Tropical Medicine, just published in the British Medical Journal quoted by the BBC. The study urges governments and international agencies to deal with the problem now. Drawing on evidence from Africa and Asia, the study shows that uncontrolled prescribing of anti-retroviral drugs is widespread and rising. Where the state sector cannot or will not provide drugs, patients who can afford them naturally purchase where they can - from doctors, pharmacies, market sellers, or relatives abroad.