Since angiogenesis is essential for the growth of any solid tumor, emerging efforts are being made to develop antiangiogenic therapy. To date, however, no antiangiogenic agent has become widely available for the clinical setting. Angiotensin I-converting enzyme (ACE) inhibitors are commonly used as antihypertensive agents and it has recently been suggested that they decrease the risk of cancer. Studies have found that an ACE inhibitor, perindopril, is a potent inhibitor of experimental tumor development and angiogenesis at a clinically comparable dose. The potent angiogenic factor, vascular endothelial growth factor (VEGF), is significantly suppressed by perindopril and also inhibits VEGF-induced tumor growth. In vitro studies showed that perindopril is not cytotoxic to either tumor cells or endothelial cells. Since perindopril is already in widespread clinical use without serious side effects, it may represent a potential new strategy for anticancer therapy.