A total of 95 patients seen in general practice with oedema associated with heart failure took part in an open study of the efficacy and tolerability of a combination tablet containing 40 mg frusemide and 5 mg amiloride. The study was of 3-months' duration and patients received a dosage of 1 to 2 tablets once daily. Efficacy was assessed by physicians' scores for ankle, leg and lumbosacral oedema and pulmonary crepitations, body weight and physicians' global clinical impression. In addition, patients recorded their symptom severity in study diaries during the first 7 days of therapy, and the day before each trial visit. On the basis of the physicians' overall impression of response to therapy, 89 (93.7%) of the patients were graded as 'excellent', 'good' or 'adequate' responders. Improvement in severity scores for oedema, crepitations and body weight also followed this pattern, although certain symptoms were mild or absent in some patients at recruitment. Nine patients were withdrawn from the study, 4 due to drug-related adverse effects. There was no evidence of any consistent change in serum potassium levels or other clinical chemistry, liver function tests or haematology during the study.