Causes. Scientists have not yet determined the exact cause of bacterial vaginosis. However, they do know that this infection is most common in sexually active women. It is linked to an imbalance between harmful and good bacteria normally present in a woman’s vagina. When good bacteria, known as lactobacilli, outnumber the unhealthy bacteria, called anaerobes, an unnatural imbalance of microorganisms disrupts the healthy environment in the vagina. Any activity that upsets this balance, such as douching, unsafe sex, or having multiple partners, can lead to the infection. Using proper hygiene practices is crucial for vaginal health. Regularly bathing and utilizing gentle, all-natural products also reduces the risk of upsetting this balance.