The growth and recovery of temporary threshold shift (TTS) produced in 15 male normal-hearing college students by exposure to noise was determined before and after a week of (1) massive doses of vitamin A (100,000 units per day), and (2) a placebo represented to the subjects as another vitamin. Neither vitamin A nor placebo produced any change in the course of the TTS. It is concluded that, as in the case of dark adaptation in vision, an excess of vitamin A has no effect on sensory adaptation, although a lack of vitamin A may retard the adaptation process.