In the vaginal washings of 100 women with symptomatic non-specific vaginitis a succinate/lactate ratio of greater than or equal to 0.4 had a diagnostic sensitivity of 80%, a specificity of 83% for this condition. The predictive value of a positive test was 94%, but that of a negative test was only 55%. A strong association between the presence of Gardnerella vaginalis, anaerobes, a vaginal pH of above 4.5, and amines was found not only in non-specific vaginitis, but also in trichomonal and gonococcal infection. A variety of primary changes may encourage the multiplication of both gardnerellae and anaerobes and their presence in non-specific vaginitis may be a secondary rather than a primary event.