As contraception after intercourse, levonorgestrel is available by prescription in the United States and in most other countries. In over 30 countries it is available without prescription.1 Levonorgestrel recently came to wide attention when the US Food and Drug Administration (FDA) acted on an application to switch the drug to non-prescription or “over the counter” status.2 The application was supported by essentially all internal scientific staff and the external advisory committee of the FDA, but the FDA rejected the application. The reason given had to do with the ability of women to understand the appropriate use of the product,3 but this issue had been explicitly discussed and settled to the satisfaction of the FDA's scientists and external advisory committee4 The FDA's explicit denial that the decision had been the result of political pressure has been received with scepticism.5–8

How should policy makers decide which drugs should be available over the counter? Practice varies widely. Travellers from developed countries are often surprised to find that antibiotics, antiarrhythmics, and many other drugs are available without prescription in other parts of the world. Even within the United States, some pharmaceuticals are available over the counter in some states but not in others.9

Marketing status is not just a choice between requiring and not requiring prescriptions. Drugs with special risks (for example, some antiarrhythmics) are often given a hyperprescription status and sometimes involve central registers of prescribers and patients. To slow the development …