Abstract: Use of the one or more oligomers of lactic acid with the following formula (I) wherein n is an integer from 2 to 25 such as, e.g., from 2 to 20, from 3 to 25, from 3 to 20, from 2 to 15, from 3 to 15, from 2 to 10, from 3 to 10, from 4 to 10, or from 4 to 9 or a lactic acid oligomeric product for the prophylaxis and/or treatment of a disease or condition that benefit of an acidic environment especially a gynaecological infection such as a bacterial infection, such as bacterial vaginosis, unspecific colpitis, senile colpitis, cervicitis, and urethritis, a fungal infection, such as candidosis (Candida albicans), cryptococcosis, actinomycosis, or a viral infection, such as Human Immunodefiency Virus (HIV), Herpes Simplex Virus (HSV), Human Papilloma Virus (HPV).