Objective To observe the effect and mechanism of Shenling Baizhu Powder（Powder of Ginseng

Poria and White Atractylodes） on ulcerative colitis（UC） rats with spleen deficiency damp encumbrance syndrome.Methods Sixty Wistar rats were randomized into four groups

i.e.Shenling Baizhu Powder group（12g/kg）

sulfasalazine group（0.5g/kg）

normal control group and model control group（normal saline

10ml/kg）

with 15 in each.The model rats were induced by environment and diet intervention combined with composite TNBS and ethanol.Fourteen days after modeling

the general conditions

score of colic injury degree

activity of superoxide dismutase（SOD） and content of malondialdehyde（MDA） were measured.Results The score of colic injury degree were significantly increased in the model control group as compared with that in the normal control group（P<0.05）.The scores of colic injury degree in the Shenling Baizhu Powder group and sulfasalazine group were significantly decreased as compared with that in the model control group（P<0.01）

especially in the Shenling Baizhu Powder group（P<0.05）.Comparing with the normal control group

the activity of SOD was decreased and the content of MDA was increased significantly in the model control group（P<0.01）.The activity of SOD was increased and the content of MDA was decreased significantly in the Shenling Baizhu Powder group and sulfasalazine group as compared with the model control group（P<0.01）

especially in the Shenling Baizhu Powder group（P<0.05）.Conclusion Shenling Baizhu Powder could reduce colon mucosa congestion

edema and ulceration

increase the activity of SOD and decrease and the content of MDA in UC rats with spleen deficiency damp encumbrance syndrome.