Objectives : In order to investigate the toxicity of rats after oral administration of Eumcheonyijin-tang extract. Methods : The experimental animals were subdivided into control, short term administration group, and long term administration group. With changes of gross appearance, the histological changes of liver and kidney were observed. Blood chemical indexes used in this study were AST, ALT, total bilirubin, albumin, BUN and creatinine in serum. Results : In the long term administration group, histological changes were detected in the liver as centrolobular disposition of fatty tissue(adipose cell), and in serum test, AST, ALT increased at 21 days after administration group, serum total bilirubin were increased 21, 28 and 35 days after administration group. So it seems to induce toxicity. Kidneys of the long term administration group revealed histological changes : increasing of connective tissue and pyknosis of glomerulus cell were observed at 28 days after administration group, and in serum test, significant changes of albumin, BUN, and creatinine were admitted. So it seems to induce toxicity. Conclusions : In long term administration of Eumcheonyijin-tang toxicity was induced.