The purpose of the research was to study clinical and immunological efficacy of a synthetic interferon inductive preparation Cycloferon-liniment («Polysan», St. Petersburg, Russia) in local treatment of some vaginal infectious diseases (nonspecific bacterial vaginitis, bacterial vaginosos and vaginal candidosis). We also studied its immunocorrective effects. The research was carried out with placebo control group. We examined 41 patients of reproductive age. 27 patients were treated with Cycloferon liniment and 14 patients received placebo course. The methods of the research included clinical, microbiological and immunilogical investigations. Clinical efficacy was assessed by the state of vaginal ecosystem; immunological efficacy was estimated by changes in immunological parameters of blood lymphocyte phenotype, non-specific indicators, immunoglobulin composition) and of vaginal secreta (immunoglobulin composition, permeability of vaginal histohaematic barrier and type of immunoglobulin production). Clinical efficacy of the preparation was up to 88, 8 %. The rate of pathologic vaginal ecosystem types was 2, 6 times lower when compared to the placebo group. The preparation had no side effects. It did not cause any allergy. We observed changes in immunological parameters of sera of the treated patients: the initially increased number of CD8+ and CD25+ lymphocytes decreased and achieved the normal level; the CD4/CD8 ratio became normal; the phagocytic neutrophil number increased. The basic mechanism of action of Cycloferon-liniment encompasses its influence on vaginal local immunity. The preparation increases permeability of vaginal histohaematic barrier; it increases local IgG and IgA concentrations owing to the enhanced diapedesis of the immunoglobulins through the vessels and to the increased local synthesis of these immunoglobulins. (Med. Immunol. 2001, vol. 3, N 1, pp 77-88)