OBJECTIVE: To investigate the efficacy of the extract from Yiyuan Yiliu Tang(益元抑瘤汤, YYYLT) on human lung adenocarcinoma cells A549 and human hepatoma cells Bel7402.METHODS: The cancer cell lines were treated with various concentrations(0, 100, 200, 300, and400 μg/m L) of the crude water extract of YYYLT and then cell viability, toxicity, cytokine secretion,and cell cycle/apoptosis were determined by MTT assay, LDH assay, and flow cytometry, respectively.RESULTS: The extract from YYYLT significantly suppressed the proliferation of the cancer cell lines and the release of interleukin-2 and tumor necrosis factor-α in a dose-dependent manner. The extract also promoted apoptosis, caused cell cycle arrest at G0/G1 phase, and increased the expression of caspase-3, B-cell lymphoma-2(Bcl-2), and Bcl-2-associated X proteins.CONCLUSION: The extract from YYYLT might be a potential treatment for human lung and liver cancers.