In this study, antioxidant and anti-inflammatory activities of water, methanol, and ethanol extracts obtained from Allium hookeri root were evaluated. The ethanol extract of A. hookeri was found to possess the strongest reducing power and also exhibited dominant effects on scavenging of nitrites, DPPH radicals, and superoxide radicals. The water extract showed more efficient DPPH and hydroxyl radical-scavenging activities than those of the methanol extract. Furthermore, the inhibitory activity against nitric oxide (NO) production in RAW 264.7 macrophages was evaluated to elucidate the anti-inflammatory properties of the extracts. Results indicated that all the extracts of A. hookeri exerted inhibitory activities against NO production, especially the ethanol extract (IC5029.13μg/mL). Total phenolic and total flavonoid contents were found to be abundant in the ethanol extract, with values of 24.96 mg gallic acid equivalent/g extract and 4.27 mg rutin equivalent/g extract, respectively. Total thiosulfinate content was determined for the first time and a high amount was present in the ethanol extract (14.2 μM/g extract). These results suggest that A. hookeri root has antioxidant and anti-inflammatory properties and could be used as a natural source for the development of pharmaceutical agents or functional foods.