The antibacterial activity of two different clotrimazole formulations was tested in vitro. A neutral vaginal tablet with 100 mg active ingredient has a partial bactericidal effect on gram-positive bacteria. A new formula containing 500 mg clotrimazole and lactic acid, designed for a one-dose therapy of vulvovaginal mycoses, shows an improved bactericidal activity against gram-positive bacteria and, owing to the lactic acid content, a broad bactericidal effect on gram-negative species.