Objectives : Anticancer and immune-modulating effects of several Korean medical prescriptions including Yukgunja-tang, Bohwa-tang, Sogam-Won, and Kamiboa-tang were investigated. Methods : In vitro anti-cancer effects were measured by cytotoxicity MTT assay using SNU-1 gastric cancer cell lines, In vivo anti-cancer effects were measured by increased life span of S-180 sarcoma-injected ICR mouse. Immune-modulating effects were analyzed by measuring hemagglutinin titer, appearance of rosette forming cells, lymphocyte proliferation, and phagocytic index in methotrexate-pretreated mice. Results : In vitro assay showed that only Sogam-won showed cytotoxic effect with $IC_{50}$ of 87.9 ${mu}g/ml$. All other prescriptions showed no cytotoxic effects against SNU-1 gastric cancer cell line. However, in vivo assay showed that Sogam-won showed lowest anti-cancer effects in contrast to its highest cytotoxic effects, Kamiboa-tang, which showed no cytotoxic effect, showed the highest in vivo anticancer effects, with increased life span of 140%. Kamiboa-tang showed significant immune-enhancing activities by significantly increasing rosette forming cells, lymphocyte proliferation, and phagocytic index in methotrexate-pretreated mice (P<0.05). Conclusion : The anticancer effect of Kamiboa-tang is not mediated by direct inhibition of cancer cells but is mediated by improving immune reactions against cancer cells.