In the last 20 years, direct-to-consumer advertising (DTCA) for prescription drugs has grown by leaps and bounds. The factors leading to erroneous prescriptions and the influence of increased advertising on the frequency of incorrect prescribing remain little understood. A review of observational and experimental studies on advertising-related prescription requests that also look at prescription appropriateness shows that DTCA increases prescription requests, the likelihood of getting a prescription, and appropriate and inappropriate prescribing. Possible reasons for wrong prescriptions in response to DTCA include what patients anticipate, not sharing enough information, and assessments of patient satisfaction.