Pharmacokinetic characteristics of metronidazole were studied in 19 pregnant women with Trichomoniasis urogenitalis who had been hospitalized for legal abortion. All patients received 250 mg or 1.0 g metronidazole (Vagimid®) per os in a single or multiple dose. Peak levels were reached 1–2 h after application. Mean serum levels of metronidazole were somewhat lower in gravidae than those in nonpregnant women. The mean elimination half-life values were 5.7 and 7.7 h after intake of 250 mg and 1.0 g metronidazole, respectively. As suggested by our pharmacokinetic results, the dosage regimen for treatment of anaerobic bacteria infection or parasitic infection in pregnant women can be the same as in nonpregnant patients.