Hepatocellular carcinoma (HCC) is one of most common types of malignant tumours. Therefore, it is very important to identify powerful drugs and their antitumour mechanisms. Corilagin has a significant antitumour potential and lower toxicity in normal cells in vitro. The IC50 values of corilagin for normal Chang-liver cells and the HCC cell lines Bel7402 and SMMC7721 were 131.4, 24.5 and 23.4 µM, respectively, in the methyl thiazolyl tetrazolium (MTT) assay. MHCC97-H xenografts in Balb/c mice intraperitoneally injected with 30 mg/kg corilagin for 5 weeks showed a 47.3% inhibition of tumour growth in vivo. Furthermore, data from flow cytometry and Western blot analyses of cell cycle and cell cycle-related proteins suggest that corilagin arrests SMMC7721 cells at the G2/M phase by downregulating p-Akt and cyclin B1/cdc2 and upregulating p-p53 and p21Cip1. In conclusion, corilagin is a potential antitumour drug that is effective in retarding the growth of HCC, which is correlated with the activation of p-p53-p21Cip1-cdc2/cyclin B1.