Purpose: The aim of this study was to evaluate the physicochemical activities and safety of extracts of Allium hookeri (A. hookeri). Methods: MTT assays of A. hookeri extracts (leaf and root, DW and EtOH) were conducted for evaluation of safety. With regard to physicochemical activity of general composition components, sulfur compounds (leaf and root, raw), anti-inflammatory effects, and antioxidant activity (leaf and root, DW and EtOH) were analyzed, and we tested whether there was any correlation between physicochemical substances and free radical scavenging activities (DPPH and ABTS). Results: In the MTT assay, the cell survival rate was >97% at concentrations of 50, 100, and 200 µg/mL of A. hookeri extracts, indicating that they were safe. All general composition components except for carbohydrate in raw leaf of A. hookeri were higher than in raw root, while sulfur level was highest in raw root. NO inhibitory effect of EtOH root extract was the highest. The DPPH and ABTS radical scavenging activities of EtOH leaf extract were the highest. Conclusion: Physicochemical substance activities (total polyphenol, total flavonoid, and sulfur) were correlated with free radical scavenging activity (DPPH and ABTS) resulting in suppression of NO production that enhances free radical scavenging activity.