Candidiasis, infection due to Trichomonas vaginalis and bacterial vaginosis (Gardnerella vaginalis and/or other species) represent the major three causes of vulvo-vaginitis. Other are rare bacterial infections and non infectious vaginitis such as allergic and post-menopausal vaginitis with epithelial atrophy. Clues for the diagnosis include the clinical features of vaginal discharge, cytological examinations, bacterial and fungal cultures. Only T. vaginalis seems to be responsible of sexually transmitted disease. All appropriate antibacterial or anticandidosic treatment are immediately effective, but the mechanisms of recurrent candidiasis and vaginosis are still unclear.