The purpose of this study was to determine the possibility of using Oenanthe javanica as a natural health food source. To accomplish this, its general and biological activities were measured. Its carbohydrate, crude protein, crude lipid, and ash contents were 44.7, 9.8, 8.9, and 27.8%, respectively. The K content was largest for minerals followed by Ca, P, and Mg, which means that Oenanthe javanica is an alkali material. The concentrations of total phenol and flavonoids of OJE were 88.9±0.46 mg GAE/g, and 28.6±0.64 mg QE/g, respectively. Gallic acid, catechin, chlorogenic acid, and caffeic acid in OJE as measured by using HPLC were 0.9±0.23, 1.2±0.19, 227.1±0.62, and 4.0±0.35 mg/g. The DPPH and ABTS radical scavenging activities of OJE were 72.2%, and 66.1%, respectively, at 1,000 µg/mL. The FRAP and reducing power of OJE were 0.79, and 0.41 absorbance units value respectively, at 1,000 µg/mL. OJE possessed significant antioxidant properties, which suggests its great potential as a functional ingredient for food applications.