Cervicovaginal secretions (CVS) from 46 heterosexual African women, attending the National Reference Center for Sexually Transmitted Diseases and AIDS of Bangui, Central African Republic, were investigated, at inclusion and after vaginal douching with water, in order, i) to determine the relationship between cervicovaginal pH and the presence of semen components [prostatic acid phosphatase (PAP) and prostatic specific antigen (PSA)] in sexually active African women; ii) to assess whether vaginal douching performed after sexual intercourse could efficiently eliminate semen components and restore cervicovaginal acid pH. At inclusion, semen components were found in 41 CVS (89%); the mean cervicovaginal pH was 6.12 (range, 3.86 to 8.33); concentrations of both PAP and PSA correlated positively and strongly with cervicovaginal pH (p < 0.001). After douching, semen components were found in only 31 CVS (67%) (p < 0.03); vaginal PAP and PSA levels were significantly decreased (p < 0.0001); PAP: -21%; PSA: -36%). Frequent persistence of semen in cervicovaginal secretions from heterosexually active African women leads to a shift from acidity to neutrality, that could favor male-to-female HIV transmission.