The ex vivo experiment demonstrates that taraxasterol is effective in inhibiting the proliferation of human hepatocellular carcinoma SK-Hep1 and HepG2 cells by upregulating the expression of histidine triad nucleotide-binding protein 1 (Hint1) and downregulating the expression of cyclin D1, which arrests the cell cycle at the G0/G1 phase. This evidence concerns the gene HINT1 and hepatocellular carcinoma.