In contrast to women with infrequent episodes of candidal vaginitis, women with chronic and recurrent candidal vaginitis do not have recognizable precipitating or causal factors. Analysis of vaginal yeast isolated from women with recurrent candidal vaginitis, although revealing a higher percentage of non-albicans Candida sp., indicates that resistance to imidazoles is not a causal factor, and other fungal virulence factors that could explain the repeated attacks have not been identified. Strain typing of sequential clinical isolates indicates a pattern of vaginal relapse rather than frequent vaginal reinfection, and attempts to reduce attacks by treating sexual partners and suppressing a gastrointestinal tract focus have failed. Recent immunological studies suggest the possibility of an acquired Candida antigen-specific immunological deficiency resulting in uncontrolled vaginal Candida proliferation and hence repeated clinical attacks. In support of the immunological hypothesis is the recent report of normal T lymphocyte suppression of Candida hyphal production.