1. Quantitative vitamin C studies done on mental patients reveal levels considerably lower than normal.2. These low levels have been, at least partially, traced to the low vitamin C allowances in most institutional diets but undoubtedly also on the unusual food habits of mental patients, depending on their delusions regarding food.3. A definite correlation has been found between the frequency of dental and gingival conditions in mental patients and their low ascorbic acid levels.4. No significant differences were found in the various diagnostic groups, except that the lowest findings were in the alcoholic psychoses.5. It is recommended that hospital diets be supplemented by an adequate vitamin C supply.