Cancer metastasis via blood vessels is a complicated process involving a number of stages. Vascularization in the cancer stroma is essential for the metastatic process. Vascular endothelial growth factor (VEGF) is an angiogenic factor, and has important roles in tumor progression or metastasis. In this study, we developed a polycolonal antibody to VEGF and examined whether the anti-VEGF antibody could inhibit the metastasis of human xenografts expressing VEGF in nude mice. The xenograft Col-23-JCK expressing VEGF formed metastatic lesions in the liver and/or pancreas when inoculated via the portal vein (splenic vein) into nude mice. The anti-VEGF polyclonal antibody inhibited metastasis to the liver and/or pancreas (4.75+/- 3.62, anti-VEGF-treated vs. 9.73 +/- 8.24, w/o anti-VEGF treatment; Student's t-test, p=0.035). Vascularity in the metastatic lesions was also decreased by anti-VEGF treatment. These results suggest that anti-VEGF antibody administration may be therapeutically useful for prevention of colon cancer metastasis.