The United Nations drug control agency is reporting a worldwide rise in the use by rapists of drugs to subdue their victims.
The agency, the International Narcotics Control Board, says that tougher measures against the most notorious date-rape drug, Rohypnol, have been successful but that sexual predators are turning to other substances subject to less stringent international controls.
The BBC reports that the board wants those substances placed on governments' lists of controlled substances lists and manufacturers to develop safety features such as dyes and flavourings.
In the UK, ketamine, an anaesthetic, has been a class-C drug since January 2006, while the solvent GBL, or gamma-butyrolactone, was one of a number of "legal highs" that became class-C drugs last year.
But both substances also have legitimate uses, making it harder to keep them out of the hands of criminals.
Drug traffickers are also increasingly using illegal pharmacies based overseas, the report says. Orders are placed via the internet or telephone call centres, with no prescription or other authorisation required.
India is identified as one of the main sources of such transactions.
