Angiogenesis is essential for the growth of solid tumors. Antiangiogenic therapy has therefore attracted considerable interest as a novel therapy for various tumors including colorectal carcinoma. We experimentally investigated the therapeutic effect of TNP-470, a nonspecific inhibitor of angiogenic factors, and vascular endothelial growth factor (VEGF)-neutralizing antibody (VEGFAb), was a VEGF-specific inhibitor, on liver metastases of colon carcinoma using a murine orthotopic transplantation model. TK-4 and TK-13 are moderately differentiated adenocarcinoma strains established in our department which express VEGF mRNA and protein. Administration of TNP-470 30 mg/kg significantly inhibited the liver metastases of both strains, as did administration of VEGFAb 100 micrograms/mouse. The therapeutic effect on liver metastases was more dominant with antiangiogenic therapy than with chemotherapy (mitomycin C). Furthermore, the sustained effect of TNP-470 induced tumor dormancy and consequently improved the survival of the animals. These results suggest that antiangiogenic treatment will be a potent therapy for liver metastases of human colorectal carcinoma in the future.