RESUMEN
<p><b>OBJECTIVE</b>To investigate the effects of Sanren decoction on the immune function of rats with spleen-stomach damp-heat (DHSS) syndrome.</p><p><b>METHODS</b>Fifty male SD rats were randomly allocated into normal control group, DHSS model group, and 3 Sanren decoction groups (high, medium and low doses). The effects of the decoction on the body mass, rectal temperature (RT), water and food intake, histopathological changes of the gastrointestinal mucosa and serum levels of interleukin (IL)-4 and interferon (IFN)-γ were evaluated.</p><p><b>RESULTS</b>The serum levels of IFN-γ and IL-4 in the model group significantly increased compared with those in the control group (P<0.01), with a slightly increased IFN-γ/IL-4 ratio (P>0.05). Sanren decoction obviously reduced the rectal temperature and significantly decreased the production of both cytokines. High-dose Sanren decoction caused more markedly decreased IL-4 level (P<0.05) to result in a significantly increased IFN-γ/IL-4 ratio (P<0.05).</p><p><b>CONCLUSIONS</b>A shift of Th1/Th2 balance toward Th1 immune response is demonstrated in rats with DHSS syndrome, and Sanren decoction produces a protective effect on the gastrointestinal mucosa by immunoregulation.</p>