HCT-116 cells (2 × 106/mouse) were injected subcutaneously into the right axilla of nude mice. Ten to 14 days later, when tumors formed, the nude mice with good growth state and unbroken tumors were used as tumor supply mice, and were then sacrificed. Tumors were dissected out under aseptic conditions, with necrotic and fibrous tissues removed. Fresh parts on the edge of tumors were cut into 1-mm3tumor blocks, which were implanted under the axillar skin of the right front legs of nude mice. With this method, three generations of mice were produced. The third-generation mice with unbroken transplanted tumor and sound growth state were sacrificed, and using the above-described method, the tumors were re-implanted and when they reached a size of 50–100 mm3, the tumor-bearing mice were randomly divided into five groups (six mice for each group): the control group (isometric normal saline), the low-, medium-, and high-dose VB groups (20, 40, and 80 mg/kg/day, respectively) and the fluorouracil (5-FU) group (1 mg/kg/day). VBand 5-FU were administered by tail vein injection. At days 1, 4, 7, 10, and 14, the long diameter (a) and the short diameter (b) of each tumor was measured, and tumor volume was calculated as [(a × b2)/2]. After 14 days of treatment, mice were sacrificed and their tumors were dissected and connective tissues were removed. The tumors were weighed. We then calculated the tumor volume inhibition rates [(1− average tumor volume of the experimental group/average tumor volume of the control group) × 100%]; and the tumor weight inhibition rates [(l − average tumor weight of the experimental group/average tumor weight of the control group) × 100%].