We investigated the effects of dietary red pepper on the energy metabolism in male subjects. In the first experiment, after havinga standardized dinner on the previous evening, the subjects consumed a breakfast (650kcal) either with or without 10g of red pepper. For 150 min after the meal, they took a rest and their expired gas was collected. During the initial 30min after the meal, the energy expenditure tended to be higher in the red-pepper diet period than in the control diet period. For the remaining 120min, no difference in the energy expenditure was found between the red-pepper diet period and the control diet period. However the carbohydrate oxidation was significantly higher in the red-pepper diet period than in the control diet period while the lipid oxidation was lower in the red-pepper diet period than in the control diet period for 150 min after the meal. In the second experiment, the subjects consumed a breakfast with 10g of red pepper after an oral administration of propranolol or a placebo. The propranolol abolished the increase in energy expenditure during the initial 30min due to the meal containing red pepper. For the remaining 120min, no difference in energy expenditure was found between the propranolol period and the placebo period. These results suggest that an increase in the energy expenditure after the meal containing red pepper appeared only immediately after the meal ingestion and a red-pepper diet increases the carbohydrate oxidation without increasing total energy expenditure for 150min after the meal. And an increase in the energy expenditure immediately after the meal containing red pepper is considered to be caused by β-adrenergic stimulation.