To develop physiological functionality of Omija extracted with water was evaluated on antioxidative activity. Omija, high acid material with pH 3.6, contain $57.5{pm}1.03%$ of moisture, and $18.8{pm}0.12%$ of crude fat. This material have $12.6{pm}0.04%$ of carbohydrate and $11.1{pm}0.07%$ of crude protein as well, but ash and crude protein contents were found less than 10%. 10 mineral contents were also found, too; K and Ca showed the highest level, then Al, Mg, Na and Mn were followed. In composition amino acid contents, glutamic acid took the largest portion, $131.7{pm}1.3$ mg/100 g, aspartic acid $51.5{pm}0.6%$, and other composition amino acid under 50%. In case of free sugar contents, 7 types were found. Most of them were glucose and fructose. Total phenolic compounds showed the highest level, $2,862.6{pm}31.7$ mg/100 g. $197.8{pm}14.6$ mg/100 g of flavonoid and $225.6{pm}18.2$ mg/100 g were included. In terms of electron donating ability, radical scavenging ability activated as the amount of Omija extract increased. In particular, Omija extract in 1,000 ${mu}g/m{ell}$ demonstrated almost similar electron donating ability, $72.4{pm}0.21%$, to BHT. It was also found that antioxidant activities of electron donating ability, SOD-like ability, hydroxyl radical scavenging ability and nitrite scavenging ability were highly promoted as Omija extract concentration increased. The nitrite scavenging ability was significant when the extract belonged to strong acid region and doping concentrations increased.