Angiogenesis is a crucial step essential for the growth, progression and metastasis of solid tumors. Substances produced by inflammatory cells, such as cytokines play an important role in the stimulation and progression of angiogenesis. In this study we investigated the anti-angiogenic effect of Biophytum sensitivum, using in vivo as well as in vitro models. In vitro antiangiogenic activity was studied using B16-F10 melanoma cell-induced capillary formation in C57BL/6 mice. Intraperitoneal administration of the extract at a concentration of 50 mg/kg significantly inhibited the tumor directed capillary formation induced by melanoma cells. The cytokine profile in the serum of these animals showed a drastically increased level of proinflammatory cytokines such as IL-1beta, IL-6, TNF-alpha, GM-CSF and the direct endothelial cell proliferating agent, VEGF. Administration of Biophytum extract could differentially regulate these cytokine's elevation. The differential elevation is further evidenced by the increased production of IL-2 and tissue inhibitor of metalloprotease-1 (TIMP-1) in the B16-F10 injected, extract treated animals. The extract of B. sensitivum at non-toxic concentrations (1 microg/ml, 5 microg/ml and 10 microg/ml) inhibited the VEGF-induced vessel sprouting in rat aortic ring assay. Moreover, B. sensitivum was able to inhibit the VEGF-induced proliferation, cell migration and capillary-like tube formation of primary cultured human endothelial cells. Furthermore B. sensitivum showed inhibitory effect on VEGF mRNA levels in B16-F10 melanoma cells. Hence the observed antiangiogenic activity of the plant B. sensitivum is exerted through its cytokine modulation activity and inhibitory activity against VEGF mRNA expression.