Women have been urged to pay a visit a nurse practitioner or GP if they are worried they have a yeast infection.
A US study shows that only 26% of women who suspect they have a vaginal yeast infection actually have one.
Findings were based on the records of 150 patients at the university's Vulvar and Vaginal Disease Clinic.
A nurse academic warned that as a result, many women are unnecessarily buying over-the-counter medicines, which could cause other problems.
Susan Hoffstetter, assistant professor of obstetrics, gynaecology and women's health at Saint Louis University School of Medicine and women's health nurse practitioner, said: 'If you treat yourself and it never goes away, you shouldn't continue to treat yourself. You're making a situation worse and you can get into cyclic episodes where you think you have a yeast infection all of the time.'
Women who thought they had a yeast infection reported vaginal discharges, which could also indicate an inflammation, dry skin tissues or a sexually transmitted infection.
Typical symptoms of yeast infections are pain or discomfort during sex, burning, redness and swelling of the vaginal area, a thick, white, cottage cheese-like discharge that doesn't smell bad and pain during urination.
Prof Hoffstetter's advice to women who think they have a yeast infection is to visit a nurse practitioner or doctor, who will do a pelvic examination or swab to detect yeast.
Ms Hoffstetter discussed her findings at an education session presented by the International Society for the Study of Vulvovaginal Disease.