Spiramycin concentrations in lung tissue were studied in patients undergoing pulmonary surgical procedures. The first group of six patients received 500 mg spiramycin iv 16 h before surgery and 500 mg at anaesthetic induction (total 1 g). The second group of six patients received three doses of 500 mg spiramycin iv 24, 16 and 8 h before surgery, and 500 mg at anaesthetic induction (total 2 g). Samples were taken from lung tissue, pleura, fat tissue and muscle. In group 1, the mean lung tissue concentration of spiramycin was 1.15 +/- 0.14 mg/kg and 7.99 +/- 2.02 mg/kg in group 2 (P less than 0.02). The differences in concentration in pleura, fat tissue and muscle samples between treatment groups 1 and 2 were not statistically significant.