Forty-one hospitalized adult patients of bronchiectasis (non-cystic fibrotic) with infective exacerbations were entered into a randomized, double-blind, placebo-controlled study comparing ofloxacin (200 mg tid) and amoxycillin (1 g tid) both orally for ten days. In the ofloxacin group (20 patients), improvement in sputum purulence was excellent in 14, and fair in five patients with one failure. In the amoxycillin group (21 patients), improvement in sputum purulence was excellent in eight, fair in five and poor in eight patients. Mean drug levels on day 5 were 4.1 mg l-1 for serum (2 h post-dosage) and 4.0 mg l-1 for sputum for ofloxacin, and 18.4 mg l-1 for serum and 0.3 mg l-1 for sputum for amoxycillin. Ofloxacin thus yielded higher sputum concentration and appeared to be more effective and also better tolerated than amoxycillin in infective episodes of bronchiectasis.