A total of 49 patients with primary reflux esophagitis were treated in a randomized controlled study at six trial centers. Treatment was given for eight weeks and consisted of daily doses of either 1 g of sucralfate suspension four times daily or one 150-mg ranitidine film-coated tablet twice daily. The evaluation of effect was based on data from 41 patients; 22 of these had received sucralfate, and 19 had received ranitidine. Reflux esophagitis was healed after eight weeks of treatment in 14 sucralfate-treated patients and in 13 ranitidine-treated patients. Alterations in the esophageal mucosa were established by endoscopic examination; the severity of these alterations was expressed in degrees using the Savary-Miller method of classification. The greater the degree of severity as assessed before treatment, the lower were the chances of the condition being completely healed. The endoscopic findings after treatment did not show any difference in the effect of the sucralfate and ranitidine treatments (p greater than 0.05). Both forms of treatment were also found to have a similar positive effect on the subjective symptoms recorded. Overall tolerance of the two forms of treatment was good. One patient treated with ranitidine had to discontinue treatment because of an allergic rash. Based on these results, sucralfate seems to be an effective alternative for the treatment of reflux esophagitis.