Asclepias curassavica. Linn, an erect, simple (or) much branched perennial herb with a somewhat woody base, belonging to the family Asclepiadaceae. It has been reported to have multiple pharmacological effect of anti-inflammatory, cardiotonic, anticancer, anthelmintic and to treat piles and gonorrhoea. It is to be expected that several activities might be related to a possible antioxidant action from this plant. The hydro alcoholic extract of Asclepias curassavica was tested in vitro for its antioxidant activities, such as DPPH radical, nitric oxide radical, superoxide anion radical, lipid peroxidation assay, hydroxyl radical, reducing power, and total phenol content. The extract exhibited scavenging potential with $IC_{50}$ value of $8.7;{mu}g/ml,;198.4;{mu}g/ml;and;21.7;{mu}g/ml$ for DPPH, nitric oxide and superoxide anion radicals. The values were found to higher than those of Vitamin-C, rutin, and curcumin, as standards. The extract showed 50% protection at the dose of $134.2;{mu}g/ml;and;41.4;{mu}g/ml$ in lipid peroxidation as well as deoxyribose degradation, those values more to that of standard, vitamin E $(IC50;values,;119.2;{mu}g/ml;and;32.5;{mu}g/ml,;respectively)$. The reducing power of the extract depends on the concentration and amount of extract. Since a significant amount of polyphenol could be detected by the equivalent to $0.0495;{mu}g$ of pyrocatechol from 1 mg of extract. It can be concluded that hydro alcoholic extract of aerial part of Asclepias curassavica could be considered as potent antioxidant, which makes it suitable for the prevention of human disease.