Licorice extracts contain various useful substances for oral health. Alkaline extract showed potent anti-HIV activity, whereas flavonoid-rich water extracts showed potent anti-HSV activity, closely correlated with polarizability, ionization potential, a number of ring systems, atomic number and mass. Licorice flavonoids showed higher tumor-specificity against human oral squamous cell carcinoma as compared with human normal oral mesenchymal cells. Glycyrrhiza, at noncytotoxic concentrations, potently inhibited the IL-1β-induced inflammation in cultured human gingival and periodontal ligament fibroblasts. Glycyrrhizin, a major component of Glycyrrhiza, showed the highest UVprotected activity. The results suggest the possible applicability of licorice extracts for several oral diseases and cosmetic products.