What is a Yeast Infection?A vaginal yeast infection is pain and irritation of the vagina and the surrounding area, called the vulva. It is caused by a large growth of the fungus or yeast in the body. Yeast infections are also known as Candida yeast infections. Yeast normally lives in the vagina in small numbers, but when the bacteria within the vagina become out of balance, the yeast will grow quickly and cause pain. Vaginal yeast infections are very common in women, but it is good to recognize that men can also get yeast infections. Yeast infections in men occur when they have unprotected sex with a partner that has a yeast infection. If both partners are not treated for the yeast infection then they can re-infect each other again and again. Most women will experience a vaginal yeast infection in their lifetime and some might even experience two or more.