This research, as a basic preliminary study for development of functional health food, is aimed at assessing the body fat reduction effect and for application to human body for such reduction in actual clinical settings by preliminary extraction of 2 types of wild edible greens, Lythrum salicaria L. and Aceriphyllum rossii. Subjects over the age of 19 and less than 60 years old with BMI value range of $23.0kg/m^2{sim}29.9kg/m^2$ were recruited through screening were divided into experimental group and control group, each with 25 subjects, through randomized allocation. With both patients and evaluators wearing blindfold, the experimental group was orally administered with 4 capsules of 500mg of composite preparation containing the extracts of Lythrum salicaria L. and Aceriphyllum rossii 3 times a day for a period of 8 weeks while the control group was orally administered with 4 capsules of 500mg of placebo (fake food) with the same appearance as the preparation administered to the experimental group 3 times a day for a period of 8 weeks. After having carried out evaluation on physical examinations (body weight, BMI and body fat ratio, etc.), laboratory tests (general blood test, biochemical test of blood and urine test), lipid test, the changes were analyzed. There was no significant change between the 2 groups and within the groups in BMI and body fat ratio, which are the primary effectiveness evaluation at each time. There was no significant difference between the 2 groups in serum lipid and WHR, obesity related KOQOL, KEAT-26 which are the secondary effectiveness evaluations. There was no change between the 2 groups and within the groups in vital sign, CBC, BC and urin test. These results suggest that Lythrum salicaria L. and Aceriphyllum rossii ext. showed no significant reduction in BMI, body fat ratio and serum lipid. Additional confirmative clinical application test is needed in the future.