Candidiasis: Overgrowth of the C. albicans yeast in the gastrointestinal tract, or infection of other body areas with this yeast. Vaginal yeast infections, some forms of diaper rash and other skin rashes that emerge in moist, warm areas of skin, and thrush (a condition characterized by patches of white inside the mouth and/or throat) are all forms of yeast infection. Candidiasis tends to develop when the normal balance of bacteria (flora) in the area is upset, as can occur with antibiotic use. Prevention measures include the use of probiotics and in some cases dietary changes. Treatment is via antifungal medications. Candidiasis is usually a minor and easily addressed problem, but can be more serious for those with immune-system disorders, such as AIDS.