Hepatic fibrosis may contribute to liver carcinoma and the mortality of patients with hepatic fibrosis is gradually increasing. However, no definitive treatment has been established for hepatic fibrosis. The hepatic fibrotic process is reversible and can be controlled; therefore, the creation of novel and effective therapeutic methods to prevent or reverse the disease is required. The aim of the present study was to identify whether protein extracts from Pacific oysters (PEPO) could alleviate the hepatic fibrosis induced by CCl4 and to examine the mechanisms involved. A total of sixty rats were randomly divided into the following experimental groups: The normal control group; the hepatic fibrosis model group; the high‑dose; medium‑dose; and low‑dose PEPO groups; and the colchicine group. The results indicated that compared with those of the model group, PEPO treatment significantly decreased the serum levels of alanine aminotransferase, aspartate aminotransferase, γ‑glutamyltransferase, alkaline phosphatase, hyaluronic acid, laminin, collagen type IV and procollagen III in rats with hepatic fibrosis. The hematoxylin and eosin staining demonstrated that PEPO markedly alleviated hepatic fibrosis. The experiments using immunohistochemistry, western blotting and quantitative PCR indicated that protein and mRNA expression levels of connective tissue growth factor (CTGF), transforming growth factor β1 (TGFβ‑1) and nuclear factor κB (NF‑κB) in the liver tissues were significantly reduced by PEPO treatment. Therefore, it was concluded that PEPO successfully alleviated hepatic fibrosis induced by CCl4 and reversed the effects of hepatotoxicity by regulating the serum levels of enzymes and decreasing the expression levels of CTGF, TGF‑β1 and NF‑κB in liver tissues. These findings may provide a novel treatment option for patients with hepatic fibrosis in the future.