C. albicans is a species of yeast which is commonly found in the mouth, intestines, and vagina as a part of the human body's normal flora and which normally does not cause problems. However, it can cause candidiasis of the mucous membranes in the mouth (also called thrush) and of the vagina (called vaginitis or simply a yeast infection). It can also cause more serious diseases in people with AIDS and in chemotherapy patients.