AIM: To detect the relationship between absolute ethanol injection quantity, the interval and formation of fibreboard,the curative effect in treatment of hepatocarcinoma and to evaluate the clinical application of percutaneous hepatic quantified ethanol injection (PHQEI) in treatment of hepatic carcinoma (HCC).METHODS: (1) Experimental study: Twenty-four human hepatic carcinoma SMMC-7721 xenografted nude mice were randomly divided into three groups: group A injected with quantified ethanol at short intervals (QESI), group B with quantified ethanol at long intervals (QELI) and group C with a small quantity of ethanol at long intervals (SQLI).The tumor tissues were sent for patho-histology and electron microscopic examinations. The diameters of tumors were measured with high frequency ultrasound before and after therapies and tumor growth index (TGI) was calculated.(2) Clinical study: Tumors of 122 cases of pathologically proved HCC were injected with quantified ethanol guided by ultrasound every 3-5 d 4-10 times per period of treatment. The quantity of ethanol was calculated according to the regressive equations where Y = 2.885X when the mass was ≤5 cm in diameter and Y = 1.805X when the mass was ＞5 cm in diameter (X is the maximal diameter of the mass with the unit cm, Y is the ethanol quantity with the unit mL). The survival rates of 1, 2, 3 and 4 years and recurrent rates in situ as well as dystopia in the liver were calculated.RESULTS: (1) Experimental study: TGI of QESI group (0.072±0.018) and QELI group (0.094±0.028) was apparently lower than that of SQLI group (1.982±0.482)(P＜0.01). TGI of QESI group seemed to be lower than that of QELI group, but it was not markedly different (P＞0.05) between two groups. Severe degeneration and necrosis could be seen in QESI group by patho-histology examination. Coagulative necrosis could be seen in most tumors of QESI group and there were no residual cancer cells under electronic microscope, while the residual cancer and inflammatory cells and fibre tissues could be seen around the tumors of QELI group. Infiltration of inflammatory cells could be seen and fibre tissues were formed. (2)Clinical study: B mode ultrasound showed that 62.5% of tumors shrank after PHQEI. The survival rates of 1, 2, 3and 4 years of the group with tumors ≤3 cm in diameter were higher than those of the group with tumors ＞3 cm in diameter. The recurrent rates of tumors in situ of the former group were apparently lower than those of the latter group.The recurrent rates of tumors in dystopia in the liver of the former group were markedly lower than those of the latter group. The 122 cases underwent a total of 1221 PEI. There were no complications such as hemorrhage and severe heart,liver and kidney functional injuries except for 1 case of melena and 4 cases of jaundice who recovered after 1-2 wk under common therapies.CONCLUSION: The experimental study shows quantified ethanol at intervals of 3-5 d could improve the curative effect of hepatocarcinoma. The clinical study shows PHQEI is an effective therapeutic method for HCC with few side-effects,and a low-cost. The treatment efficacy is more remarkable for tumors ≤3 cm in diameter.