Preparation of a stable aqueous gel (A) containing metronidazole (I), comprises: forming a solvent medium comprising water and propylene glycol; dissolving (I) in the solvent medium, optionally followed by diluting the medium with water to obtain a metronidazole solution; and mixing the solution with a gelling polymer for gellating the composition. An independent claim is included for a composition obtained from the stable aqueous gel (A). ACTIVITY : Dermatological. MECHANISM OF ACTION : None given.