PURPOSE: Hyperlycemia after brain injury is known to be a risk factor that is correlated with hospital infection, mortality and the length of the hospital stay. There have been some reports about the use of a reduced-carbohydrate, modified high fat enteral formula for improving the blood glucose control and clinical outcomes of patients with type 2 diabetes. This pilot study evaluated the glucose control of brain-injured patients who were admitted into the neurointensive care unit (NCU) and they received either standard formula or high fat formula. METHODS: Fourteen subjects were collected and they were divided into the experimental (high fat formula) and the control (standard formula) groups. We investigated the blood glucose levels, the total dose of insulin used, the number of patients who received insulin, the rate of hospital infection, the number of hospital days, the number of NCU days, the days of mechanical ventilation, the body mass index and the mental status of the subjects. RESULTS: The hospital infection rate of the control group was higher than that of the experimental group, but the daily blood glucose level, the number of patients who received insulin and the total dose of insulin used were not statistically different between the two groups. The number of hospital days, the number of NCU days and the days on mechanical ventilation or the number of patients on mechanical ventilation were lower in the experimental group than that in the control group, but there were no statistically significant differences. CONCLUSION: These results suggest that the use of high fat enteral formula as compared to standard formula may decrease the hospital infection rate in critically ill patients after brain injury. But high fat formula did not have beneficial effects on the blood sugar level and insulin dosage.