Salacia reticulata is a plant widely known in Sri Lanka to be effective for the prevention of hyperglycemia. It has been shown that an aqueous extract from the stem of Salacia reticulata (SRE) has an inhibitory effect on alpha glucosidase activity and can thereby suppress postprandial hyperglycemia in humans. In this study, a placebo-controlled, cross-over trial was performed to evaluate the clinical usefulness of SRE for prevention or treatment of type 2 diabetes. The study subjects were 20 individuals (10 males and 10 females, average age 58.0±15.5yr) with type 2 diabetes. All revealed fasting hyperglycemia but were not on drug therapy. The subjects were divided into two groups, each of which was kept for six weeks on a SRE-containing diet (240mg/day) and a control-diet (placebo), respectively. After 6 weeks, the groups were crossed over, and another set of examinations was performed. Blood samples were obtained for laboratory examination before and after each set. The results indicated that the SRE-containing diet group achieved significant reductions in fasting plasma glucose levels, HbA1C and BMI. In contrast, no changes were observed in the control-diet group. During the trial, no severe side effects of the diet were observed in either group. Thus our present findings suggest the usefulness of a SRE diet for the health care of individuals with mild type 2 diabetes.