BACKGROUND: The factors that drive overtreatment of gastroesophageal reflux disease (GERD) are not well understood, but it has been proposed that the use of the “GERD” disease label could perpetuate use of medication in otherwise healthy infants. METHODS: To determine if use of the disease label GERD influences parents’ perceived need to medicate an infant, we surveyed parents in a general pediatric clinic. Parents were given a hypothetical clinical scenario describing an infant who cries and spits up excessively but is otherwise healthy. Using a 2 x 2 factorial design, parents were randomized to receive a scenario in which the doctor either gave a diagnosis of GERD or did not provide a disease label; additionally, half of parents were told that existing medications are probably ineffective, whereas the rest were not given any effectiveness information. We measured parent interest in medication, perception of illness severity, and appreciation of medication offer. RESULTS: Parents who received a GERD diagnosis were interested in medicating their infant, even when they were told that the medications are likely ineffective. However, parents not given a disease label were interested in medication only when medication effectiveness was not discussed (and hence likely assumed). CONCLUSIONS: Labeling an otherwise healthy infant as having a “disease” increased parents’ interest in medicating their infant when they were told that medications are ineffective. These findings suggest that use of disease labels may promote overtreatment by causing people to believe that ineffective medications are both useful and necessary.