A crossover study was conducted to evaluate suppressive effect of a commercially available green juice (Katuna-Aojiru;Egao Co., Ltd.) containing mulberry leaf powder as the main ingredient on postprandial hyperglycemia. The blood glucose and iAUC (0-120min) values after loading cooked white rice were significantly lower with the consumption of Katuna-Aojiru than with the consumption of water. Katuna-Aojiru is effective in controlling postprandial blood glucose.