background: esomeprazole, an s-isomer of omeprazole, is the first proton pump inhibitor developed as an optical isomer, and it has shown high healing rates in erosive esophagitis. aim: to evaluate the efficacy and tolerability of esomeprazole in subjects with erosive esophagitis, according to the los angeles classification study design: an open, multi-center clinical study. material and methods: two hundred and eighteen subjects with reflux esophagitis confirmed by endoscopy were included in an open, multi-center study in brazil. all of them received esomeprazole 40 mg, once daily, for a 4-week period. subjects who had unhealed esophagitis by week 4 continued the treatment for another 4 weeks. the primary efficacy endpoint was the healing rates by weeks 4 and 8. the secondary endpoints were the number of patients with symptom resolution by week 4, the number of days to sustained symptom resolution, number of symptom-free days and nights and safety and tolerability of the drug. results: healing rates by weeks 4 and 8 were 82% (confidence interval: 77.4%-87.6%) and 96.1% (confidence interval: 93.5% - 98.8%), respectively. ninety-nine (99%) of the patients had heartburn resolution by week 2. the most common adverse events were headache (4%), diarrhea (2.6%) and epigastric pain (2.2%). conclusion: for the studied period, esomeprazole was shown to be a safe and well-tolerated drug, providing significant healing rates of mucosal breaks, regardless of la classification, in patients with erosive esophagitis. esomeprazole was also shown to be effective in quickly relieving symptoms.