This study was to investigate the effects of Bo-Jung-Chi-Seub-Tang administration on body composition, blood biochemistrical factors and hormonal changes during 2 weeks Weight Reduction in TaeKwonDo Athletes. 10 subjects were belong to be in elite athletes of KNUPE. They were divided two groups(administration group and non-administration) by 5 subjects in each group randomly. they were measured about body composition(% Fat, Fat Wt, LBM, TBW), Blood Biochemistrical Factors(glucose, TG, total protein, albumin, BUN, Uric acid, Ca, Pi, Mg) and Hormonal Changes(Renin, Aldosteron). As the results of the experiment, conclusions were made as follows: In terms of % Fat, Fat W.T., Mg, TG, Renin, it was shown significant differences between two groups. Although there were no significant differences, rate of weight reduction and levels of LBM, BUN in Bo-Jung-Chi-Seub-Tang administration group were changed more lower than non-administration group.