Abstract: OBJECTIVE To explore the anti-ascites and anti-diarrhea effects of Kansui Radix and vinegar-baked Kansui Radix. METHODS Dichloromethane and non-dichloromethane fractions were extracted from Kansui Radix with dichloromethane and 95% ethanol in turn. The ascites volume， fecal water content， urine volume， intestinal expressions of AQP1， and AQP3 proteins were measured as indexes to screen the effective fraction and investigate the anti-ascites and anti-diarrhea effects of dichloromethane fraction before and after vinegar-baked. At the same time， the relative content changes of dichloromethane fraction before and after vinegar-baked were analyzed by mass spectrometry. RESULTS Compared with the model group， the number of ascites and the expressions of AQP1 and AQP3 in duodenum， jejunum， ileum， and colon of mice in the total-extract Kansui Radix group and high-dose dichloromethane fraction group were significantly decreased， while fecal water content was significantly increased， and urine volume was not changed. The non-dichloromethane fraction group did not notably influence the ascites and fecal water content， indicating that the dichloromethane fraction of Kansui Radix was the main effective fraction. Compared with the model group， the high-dose dichloromethane fraction of vinegar-baked Kansui Radix could significantly reduce the ascites volume， increase the fecal water content， and significantly reduce the expression of AQP1 and AQP3 protein in the duodenum， jejunum， and ileum， but had no significant effect on the expressions of AQP1 and AQP3 in the colon. Compared with the group of dichloromethane fraction of raw Kansui Radix， the ascites volume of the vinegar-baked dichloromethane fraction was significantly increased， and the fecal water content was significantly decreased. Besides， Kansui did not affect the survival rate or apoptosis of cancer cells in ascites. Mass spectrometry analysis showed that terpenoids mainly concentrated in dichloromethane fraction， 12 of the 16 terpenoids decreased， and 4 of 16 increased after vinegar processing. CONCLUSION The "removing water retention by purgation" effect of Kansui Radix was retained after vinegar processing. Vinegar-baked weakened the purgative effect， which may be related to the change of terpenoid composition.