After the i.v. administration of a single 10 mg/Kg dose of [14C] teicoplanin to rats, no substantial differences were found between males and females as regards the hematic profile, the excretion pattern and tissue distribution. About 74% of the administered radioactivity was recovered in the 0-120 hours interval and more than 90% of this amount was found in the first 24 hours. In the 0-120 hour interval, 7% of the dose was excreted with the faeces, while the total 14C excreted (including the cage washing) was 82% of the dose. A high affinity of [14C] teicoplanin for the kidneys and especially for the cortex area was displayed in the distribution study. Similar findings were observed when 7 intravenous doses (10 mg/Kg each) were given to male rats at 24 hour intervals. The percentage of the total dose found in urine seven days after the last administration remained close to 70% and also the excretion data observed in each collection interval after the last treatment were comparable with those obtained in the single dose study. The distribution in tissues was very similar to that of the single dose experiment. The high 14C concentration level found in the kidneys of animals killed at 5 min after the last treatment was cleared with a disappearance rate comparable with that observed in the single dose experiment.