The International AIDS Society says policies criminalising drug use are increasing the spread of HIV-AIDS.
The society says current drug policies have led to increased crime, violence and the destabilisation of entire states without any evidence that drug use or supply has dropped.
In some parts of the world, such as eastern Europe and central Asia, it says injecting drugs is the main cause for the spread of HIV.
The society is calling for widespread needle and syringe programmes, as well as access to substitution therapy in which illegal drugs are substituted for less harmful substances.
