Abstract: Angiogenesis is a process by which new blood vessels are formed from the pre-existing blood vessel. Orthosiphon stamineus Benth. OS has been used as a medicinal herb for many centuries. Due to the presence of high level of anti-oxidants and phenolic content compounds in OS and the effect of anti-oxidants and phenolic compounds being anti-angiogenic, the perturbation of new blood vessels ability of OS was tested. Dry powdered leaves of the OS plant were extracted with Petroleum Ether (PE), chloroform (CE), methanol (ME) and water (WE) by using sequential cold maceration method. The ME of OS has the highest anti-angiogenic activity (93.28±1.24%) in the rat aortic assay followed by CE (85.55±1.64%), PE (51.54±4.12%) and WE (50.22±1.23%) in descending order of reactivity. The methanol extract was also found to have potent anti-oxidant activity in the1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity assay. The IC50 value was measured to be 0.286 mg mL-1. The total phenolic content of 1 mg mL-1 of methanol extract was equal to 38.27%.