Infection, yeast: Infection due to fungal organisms which have the characteristic of being single-celled, usually rounded and reproduce by budding.
Most yeast are harmless (some are used in baking and brewing). Yeast is commonly present on normal human skin and in areas of moisture, such as in the mouth and vagina, usually without any problems.
However, yeast can cause disease in humans. For example, the yeast Candida (once called Monilia) causes thrush (oral infection) and diaper rash in infants, fingernail infections, vaginal area infections in women after pubertyInfections from yeast can be serious in those with immune deficiencies.