Prescribing a medication for a condition not described in the label approved by national regulatory bodies (in Switzerland, Swissmedic) is called "off-label" prescribing. Unlicensed drug use is common in all fields of medicine and may be encountered in therapeutic guidelines. The term does not imply improper nor illegal use, and may provide the only available treatment for "orphan" conditions, or for certain populations (children, pregnant women, very old patients). Off-label drug use should be based on sound scientific evidence of efficacy and safety. In Switzerland, patients need to be informed that health insurance coverage is not guaranteed with off-label use. The prescribing physician bears the responsibility of off-label use with the possibility of unanticipated risks, and should therefore be prepared for possible malpractice suits.