Ocimum gratissimum found in tropical regions is a traditional herb commonly which prevents free radical damage and protects liver from oxidative stress and fibrosis. Ocimum gratissimum polyphenol extract (OGPE) was purified by resin tube to 33.24% polyphenol and 8.2% flavonoid, which were three-fold higher compared with the pre-purification concentrations. The abstract was used to determine if the antioxidant components in the O. gratissimum extract (OGE) were responsible for protective effects on liver fibrosis. High-performance liquid chromatography analysis revealed that the content levels of catechin, caffeic acid and epicatechin in OGPE also increased three-fold. Male Wistar rats were administered with carbon tetrachloride (CCl₄) and varying amounts of OGPE doses [0-12 mg/kg body weight (BW)] or OGE dose (40 mg/kg BW) for 8 weeks. Results showed that OGPE at 12 mg/kg BW, similar to OGE at 40 mg/kg BW, maintained the liver weight, significantly ameliorated CCl₄-induced steatosis, and mitigated other pathological changes. OGPE (12 mg/kg BW) also maintained the levels of serum alanine aminotransferase and aspartate aminotransferase, as well as the levels of malondialdehyde, catalase and α-smooth muscle actin in liver tissues from CCl₄-induced changes. These findings suggest that antioxidant components in OGPE were the major factors that prevented liver fibrosis. Moreover, higher polyphenol concentrations were necessary for higher effectiveness.