This study was designed to investigate the effects of a cyclooxygenase (COX)-1 inhibitor, SC-560, administered in combination with taxol, on the molecular mechanisms of antitumor efficacy in a SKOV-3 human ovarian carcinoma cell xenograft-bearing mouse model. The mice were treated with 6 mg/kg/day SC-560 by gavage twice every other day and 20 mg/kg taxol by intraperitoneal injection once a week for three weeks. Microvessel density (MVD) and vascular endothelial growth factor (VEGF) mRNA levels of ovarian cancer were detected in the tumor tissues using immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR), respectively. The index of proliferating and apoptotic cells in the tumor tissues was determined by staining for Ki-67 and using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method, respectively. On day 7 after the end of administration, the tumor volume of mice in the combination group was reduced by 55.35% compared with that of the control mice, and the difference was statistically significant (P<0.05). In the combination group, the expression of VEGF, MVD and the cell proliferation index were inhibited significantly, while the apoptotic index was notably increased (all P<0.01, compared with the control group). Our results indicate that the molecular mechanisms of the antitumor efficacy of SC-560 combined with taxol therapy may act in part by inhibiting tumor angiogenesis, reducing cell proliferation and inducing cell apoptosis.