Scutellaria barbata D. Don (S. barbata), a traditional Chinese medicine, is used to treat cancers, inflammation, and urinary diseases. This study aimed to determine any protective effects of S. barbata crude extract (CE-SB) against rat liver tumorigenesis induced by diethylnitrosamine (DENA). Liver malfunction indices in serum were measured by biochemical examination. Hematoxylin and eosin staining was performed to examine liver pathology. Contents of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured in liver homogenates to evaluate oxidative stress. The levels of liver malfunction indices in the CE-SB groups, especially in the CE-SB high dose group, were lower than that of the model group (P<0.05). The results from histological examination indicated that the number of liver nodules in the CE-SB groups decreased compared with the model group (P<0.05). Content of MDA determined in liver was significantly decreased, and level of SOD elevated by CE-SB. CE-SB can inhibit experimental liver tumorigenesis and relieve hepatic injury in rats.