Offlabel use of a drug refers to a doctor prescribing a drug for a use that it has not been governmentally approved. This can occur because doctors can prescribe medications for any reason. Examples of off-label use include the use of Tegretol, which is labeled as an anticonvulsant. but is also a common standard treatment for bipolar disorder and the use of some drugs to induce abortions.

While it is legal for a doctor to prescribe a drug for offlabel use, it is illegal for a drug manufacturer to market a drug for offlabel uses.