A BSTRACT Liriope platyphylla and Asparagus cochinchinensis have been utilized as adjunctive therapies for disorders involving immune dysfunction in Korea. This study investigated the antioxidant and nitric oxide (NO) production inhibitory activities in different extracts of the two plants. The antioxidant activity of the tuber-derived extracts was assessed in vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. The cell of RAW 264.7 macrophages were treated with extracts from two plants, and cell viability and nitric oxide (NO) production was determined using the MTT and Griess assay, respectively. The ethanol extract of L. platyphylla showed the highest antioxidant activity, showing the lowest IC 50 values of 132.14 ± 2.37 μg/mL in the DPPH assay and 183.82 ± 3.24 μg/mL in the ABTS assay. All tested concentrations of the ethanol extract from L. platyphylla maintained cell viability above 100%. Neither ethanol nor hot water extracts of the two plants induced cytotoxicity. Moreover, NO production in RAW 264.7 macrophages was inhibited in a concentration-dependent manner by the tested extracts. These results provide scientific backing for the traditional use of the two plants and suggest that the in vitro antioxidant and NO inhibitory properties may have potential applications in functional foods, pharmaceuticals, and cosmeceuticals.