Gastroesophageal reflux has been named as a possible etiologic factor in infant asthma. We studied 28 boys and six girls aged 19.4 +/- 4.8 months whose asthma began at the age of 7.5 months (1 to 28 months). A common protocol including allergy tests and 24-h intraesophageal pH monitoring (IEpHM) was used. Patients with pathologic 24-h IEpHM were treated with cisapride while the rest were considered the control group. Symptoms score and drug consumption were evaluated in both groups, and 24-h IEpHM was repeated at 4 months. IEPHM was pathologic in 65.6% of the infants. In the cisapride group, wheezing crisis frequency decreased from 4.9 +/- 2 to 0.75 +/- 1.2 (p < 0.0002), and only 10% of patients needed basic pharmacologic treatment. The second IEpHM was normal in eight cases, pathologic in six and was not performed in seven. In the controls, wheezing crisis frequency decreased from 4.6 +/- 2.4 to 0.75 +/- 1.8 (p < 0.01), but 44% needed basic pharmacologic treatment (p < 0.05). In conclusion, gastroesophageal reflux is a frequent but not universal finding in infants with asthma; and cisapride treatment spectacularly reduces wheezing crisis frequency and antiasthmatic drug consumption in these patients.