OBJECTIVE To evaluate the pharmacokinetic profile of ofloxacin in healthy volunteers after single oral doses of 600 and 800 mg. METHODS Seven healthy volunteers were administered 600 and 800 mg of ofloxacin on two occasions with an interval of one week. Paired samples of blood and saliva were collected after 1, 2, 3, 6, 9, 12, 24, 32 and 48 hours post-dose. Urine samples were collected over a period of 0-6, 6-12 and 12-24 hours. Concentrations of ofloxacin in plasma, saliva and urine were assayed by high performance liquid chromatography. RESULTS Increases of 22% in peak plasma concentration (Cmax) and 40% in area under the concentration-time curve (AUC0-24) were observed with the 800 mg dose. The other parameters, namely time to attain Cmax, half-life, the apparent volume of distribution, plasma and renal clearance and percentage of dose excreted in urine over 24 hours were independent of doses. The mean ratios of the concentration in saliva to the concentration in plasma ranged from 0.4-0.6, and the correlation coefficient was 0.94. CONCLUSIONS Dose proportionality was observed in Cmax and AUC0-24 when 600 and 800 mg doses of ofloxacin were given. Ofloxacin determined in saliva seems to be suitable for therapeutic drug monitoring.