The pH of vagina in adults is

The vaginal secretion is small in amount in healthy women and consists of white coagulated material. When it is examined under the microscope, squamous cells which have been shed from the vaginal epithelium and Doderlein's bacilli alone are found. Doderlein's bacillus is a large gram-positive rod-shaped organism, which grows anaerobically on acid media. The vaginal secretion is acidic due to the presence of lactic acid, and this acidity inhibits the growth of pathogenic organisms. The pH of the vagina averages about 4.5 during reproductive life. The acidity, which is undoubtedly oestrogen-dependent, falls after menopause to neutral or even alkaline. Before puberty, the pH is about 7. This high pH before puberty and after menopause explains the tendency for the development of mixed organism infections in these age groups.