A vaginal yeast infection, also known as vaginal candidiasis, genital candidiasis, or vulvovaginal candidiasis (VVC), is an infection involving a type of fungus, or yeast. The fungus most commonly associated with vaginal yeast infection is called Candida albicans, which account for up to 92% of all cases, with the remainder due to other species of Candida. These fungi can be found all over the body and are normally present in warm and moist areas of the body. Studies have shown that up to 20% to 50% of all women normally carry yeast in the vagina without the presence of symptoms. When C albicans in the vagina multiplies to the point of infection, this infection can cause vaginal inflammation, irritation, odor, discharge, and itching.

Certain types of bacteria that live naturally in the vagina usually keep C albicans from growing out of control. If the balance of these microorganisms becomes upset, C albicans may be allowed to grow uncontrollably and lead to symptoms. The use of certain medications including antibiotics, changes in hormone levels, or certain diseases are examples of factors that can allow a vaginal yeast infection to develop.

Vaginal yeast infections are extremely common. Seventy-five percent of all women develop a yeast infection at some point during their lives.

A vaginal yeast infection is not considered a sexually-transmitted infection (STD), but 12% to 15% of men develop symptoms such as itching and penile rash following sexual contact with an infected partner.

Under normal circumstances, a vaginal yeast infection is not serious and can be treated with medications. However, a vaginal yeast infection can be a sign an underlying, more serious condition or can lead to serious complications, especially if left untreated.