The curative effects of Panax ginseng on hepatocellular carcinoma (HCC) in rats induced by diethylnitrosamine (DEN) were further studied. The size of cancerous nodes was quantitatively measured by image analysis instrument. The hepatocellular hyperplastic foci were quantitatively analysed with gamma-GT stain under microspectrophotometer. Pathological changes of hepatocytes were observed under light and electron microscope. The results of the investigation indicated that ginseng had significant inhibitory effect on HCC in rats induced by DEN and prolonged the survival time of the rats with HCC. The mechanism of inhibition of the development of HCC by ginseng was also preliminarily approached.