To study the prevalence and the number of lactobacilli in normal subjects and in women with bacterial vaginosis (BV). The studied subjects consisted of 60 normal and 60 BV women. The diagnosis of BV was based on at least three of five indicators of Chandeying criteria. The vaginal specimens were collected and cultured on MRS plates for determination of lactobacilli counts. The number of lactobacilli was highly significant (p < 0.001) in the women with diagnosis of BK and the mean count of lactobacilli in BV was markedly decreased (5.3 +/- 1.8 log colony-forming unit--CFU/ml), compared with normal women (8.8 +/- 2.9 log CFU/ml). Among the treated BV group, follow-up vaginal specimen was encountered in 47 of 60 cases (78.3%). The proportion of lactobacilli isolation was slightly increased from 12 (25.5%) to 15 (31.9%) in 47 cases. Concordance with quantitative settlement of lactobacilli in BV was increased from 1.4 +/- 2.6 log CFU/ml, to 1.8 +/- 2.9 log CFU/ml in treated BV. Treated BV the lactobacilli had not restored significance (p = 0.5831), as well as the total bacteria. Lactobacilli dominantly occur in healthy women, and markedly decline in BV. However, the vaginal ecosystem is dynamically changed in the lactobacilli of either normal or BV women.