Prescribing medications for indications that are not approved by the Food and Drug Administration—so-called off-label prescribing—is common. Although it is invariably well-intentioned, this population-based study demonstrates that off-label prescribing is a risk factor for medication errors. The study used the electronic medical record in Quebec that required physicians to enter the reason for prescribing or discontinuing medications to analyze the frequency of off-label prescribing and adverse events associated with this practice. Off-label prescribing was associated with a higher adverse drug event risk, especially when there was no convincing scientific indication for the unapproved use (which was the case in more than 80% of off-label prescriptions). The accompanying editorial notes that the FDA is under pressure to relax restrictions on marketing of drugs for off-label purposes and raises the concern that eliminating such restrictions could expose more patients to adverse events.