Codonopsis lanceolata is widely consumed in South Korea; however, its medicinal applications have not been explored in detail. The present study aimed to evaluate the xanthine oxidase (XO) inhibitory activity, reducing power, immune activity, and cytotoxicity of 30% ethanolic extracts of C. lanceolata roots stored at different temperatures (5, 15, 25, 35, and 45°C) and for different storage periods (0, 15, 30, 45, 60, 75, and 90 days). The growth of human T and B cells increased when treated with the root extracts stored at low temperatures for a short period, in a concentration-dependent manner. The XO inhibitory activity of the C. lanceolata roots stored at 5°C and 15°C was higher than for those stored at 45°C. The XO inhibitory activity of the C. lanceolata roots gradually deceased with increasing storage period. The reducing power of the extracts increased significantly in a concentration-dependent manner. Reducing power of the root storage temperature for all temperatures and storage periods using 5 mg·mL -1 extract was higher than that for the other extract concentrations. Cytotoxic activity of C. lanceolata roots on human cancer cell lines (e.g., HeLa, Calu-6, and MCF-7) decreased as storage temperatures decreased from 45°C to 5°C. The cytotoxic effect on the MCF-7 cell line was relatively higher than that on the HeLa and Calu-6 cell lines. The results suggest that the root extract of C. lanceolata can be used to modulate immune response and is also a natural food additive with excellent physiological functionality.