Nystatin is an antifungal medication. It is used to treat Candida infections of the skin including diaper rash, thrush, esophageal candidiasis, and vaginal yeast infections. It may also be used to prevent candidiasis in those who are at high risk. Nystatin may be used by mouth, in the vagina, or applied to the skin.

1. Nystatin is often used as prophylaxis in patients who are at risk for fungal infections.
2. It is prescribed in units, with doses varying from 100,000 (for oral infections) to 1 million (for intestinal ones). As it is not absorbed from the gut, it is safe for oral use and does not have problems of drug interactions.
3. It is also used in cellular biology as an inhibitor of the lipid raft-caveolae endocytosis pathway on mammalian cells, at concentrations around 3 µg/mL.
4. In certain cases, nystatin has been used to prevent the spread of mold on objects such as works of art.
Nystatin is also used as a tool by scientists performing "perforated" patch-clamp electrophysiologic recordings of cells. When loaded in the recording pipette, it allows for measurement of electrical currents without washing out the intracellular contents, because it forms pores in the cell membrane that are permeable to only monovalent ions.