A healthy vagina
A healthy vagina has large colonies of lactobacilli (or lactic acid bacteria, belonging to the so-called probiotics), which make up the essential part of the natural vaginal flora. As their name suggests, these bacteria produce lactic acid to create for themselves an environment in the vagina with a pH of 3.8 to 4.4 which is optimally acidic. Bacteria that cause disease do not grow well at this pH, and can only reproduce with difficulty. Lactobacilli therefore produce natural protection in the vagina from infection.