The role of OA in suppressing TGF‐β1‐induced EMT in HCC cells was confirmed by the decreased levels of N‐cadherin, vimentin, MMP2, MMP9, Twist1, and PAI‐1 expression, while the E‐cadherin level was raised upon treating SMMC‐7721 cells with OA. The gene discussed is TGFB1; the disease is hepatocellular carcinoma.