A Korean traditional herbal formulation, Sihoga-Yonggol-Moryo-Tang (SGYMT), is being used for the treatment of many diseases such as tumor, neuropsychiatric, and vascular disorders. The extracts prepared from SGYMT and its herbal ingredients were assayed for the inhibitory effects on tumor-specific matrix metalloproteinases-2 and -9 (MMP-2/9) activities using gelatin zymography. The results showed that SGYMT decreased the gelatinolytic activities of MMP-2 and -9, which were secreted from SK-Hep1 cells. The IC(50) values of SGYMT against these enzymes were 85 and 145 micrograms ml(-1), respectively. The cytotoxocities of SGYMT and its ingredients on human hepatocellular carcinoma (HCC) cell, SK-Hep1 cells, were very low (IC(50)>150 micrograms ml(-1)) as measured by the XTT assay method. The extract were then investigated the inhibitory effect on the invasion of SK-Hep1 cells using matrigel precoated transwell chambers. The results showed that SGYMT effectively inhibited the invasion of SK-Hep1 cells as compared with the control groups. In addition, among herbal ingredients of SGYMT, the bark of Cinnamomum cassia BLUME (Cinnamomi Cortex) and roots of Scutellaria baicalensis GEORGI (Scutelleria Radix) have shown significant inhibition against MMP-2 and -9 activity and invasion of SK-Hep1 cells. From these results, it was suggested that SGYMT could be used as potential anti-tumor agent.