Objective To discuss the possible mechanism of Dahuang Lingxian Capsule （Capsule mainly consisting of rhubarb and clematis chinensis for treating the gallstones） on the prevention and treatment of gallstone from the viewpoint of transcription.Methods Sixty general guinea pigs were randomized into 3 groups with 20 in each.The model group and Dahuang Lingxian Capsule treated group （briefed as treated group） were fed with lithogenic diet to induce gallstones.The treated group was administered Dahuang Lingxian suspension by lavage ever since the beginning of model making.The model and control groups were given the equal volume normal saline by lavage.Eight weeks later the gallstone formation rate was determined.Real-time fluorescent quantitative PCR was adopted to detect the expressions of CYP7A1 mRNA in the liver tissues of all groups.Results The gallstone formation rate of the model and treated groups were 100% and 50% respectively.Compared with the model group

the gallstone formation rate of the treated group was significantly lower （P<0.01）.The expression of CYP7A1 mRNA of model group was significantly decrease than that of the control group （P<0.01）

while the CYP7A1 mRNA expression of the treated group was 2.13 times of that of the model group （P<0.01）

the difference was significant （P<0.01）.Conclusion Dahuang Lingxian Capsule is effective in preventing the gallstone formation

the mechanism may be associated with its function in alleviating the damage of liver cells and stabilizing the expression of CYP7A1 mRNA indirectly.