Oral thrush can be easily treated with a mouth gel bought from a pharmacy. Treatment oral thrush. Thrush is an infection caused by a fungus called Candida. Jump to What types of doctors treat oral thrush? - Antifiungal medicines may be used to treat thrush. If an adult patient is diagnosed with a mild case of thrush, the doctor may prescribe an antifungal mouthwash (nystatin) or lozenges (clotrimazole [Mycelex]) for short-term use.