Thirty-one cases of pivmecillinam-associated oesophagitis or ulceration verified at endoscopy have been reported in Sweden between 1978 and 1987. There were 29 women and two men of average age 30 years (range 15-77 years). Dysphagia and retrosternal pain often developed within the first days of treatment and resolved without complications within days of stopping treatment. Based on sales and prescription data, this complication appears to be rare, with 25-36 reported cases per million treatment courses. Further galenical development of the tablets and better patient information should reduce the number of patients injured.