We studied the effects of an alginate compound (Gaviscon) on the frequency and the duration of gastroesophageal reflux (GOR) episodes in children. Twenty infants and children with characteristic symptoms of GOR were divided at random into two groups which were given either Gaviscon (ten patients, mean age: 21 months) or a placebo (ten patients, mean age: 35 months). A continuous pH probe monitoring of the lower oesophageal third was performed in all the patients before and after 8 days of treatment. Before the trial, sensitive pH monitoring variables of acid reflux (Euler-Byrne index, percentage of total reflux time per 24 h, mean duration and percentage of reflux time during sleep, total number of reflux episodes per 24 h and number of reflux episodes per 2 h post-cibal periods) were abnormal in all the patients tested. The oesophagram revealed a GOR in 13 of the 20 patients; none of the children who underwent an endoscopy had evidence of oesophagitis. Episodes of regurgitation reported by the parents decreased during Gaviscon therapy while no clinical improvement was noticed in the placebo group. No adverse effects were observed. After 8 days of treatment with Gaviscon, results of all the pH monitoring variables were significantly (P less than 0.05) reduced between -35% and -61% of the initial values recorded. In the placebo treated group, the mean values remained little changes (-9.5 to +8.2% of initial values). These data suggest that Gaviscon may prove useful in the medical management of GOR in infants and children.