The group of inventions relates to medicine, specifically to gynecology, and can be used to evaluate the acid/base condition of female sex organs. To this end, a vaginal mirror and a pH meter probe are inserted into the vagina. Next, the pH is measured and compared with reference values. Moreover, a subsequent pH measurement is taken in the region of the external os of the uterine cervix in the posterior vaginal fornix. Additionally, a method of evaluating the acid-base condition of female sex organs is proposed that includes measuring pH in the cervical canal and/or in the region of the external os and/or the pH in the uterine cavity and/or on the uterine mucosa. The group of inventions makes it possible to more precisely determine the pH of female sex organs for the diagnosis and evaluation of treatment of inflammatory diseases of internal sex organs and to predict the result of in vitro fertilization in women with infertility.