Aim: 13 C-butyrate breath test is a non-invasive method for detecting inflammation in experimental colitis. We investigated whether this test could assess the anti-inflammatory effect of kampo medicines in dextran sulfate sodium salt (DSS)-murine colitis. Methods: 13 CO 2 excretion was measured on 13 C-butyrate breath test, after rectal instillation of butyrate in a DSS colitis model. Colon length, myeloperoxidase activity, and histological damage were also analyzed to evaluate inflammation. Results: 13 CO 2 excretion in the DSS groups was significantly lower than in the normal group. Orengedokuto (OGT) and saireito (SRT) improve inflammation in DSS murine colitis, and this was reflected in the significantly higher 13 CO 2 excretion in the OGT-and SRT-treated DSS murine colitis groups compared with the vehicle (i.e. control) group. Conclusion: 13 C-butyrate breath test is a new non-invasive evaluation and screening method for the anti-inflammatory effect of kampo medicines.