Animal studies and clinical trials have documented therapeutic effects of melatonin.20-23 Systemic and local use of melatonin in rats with lipopolysaccharide-induced periodontitis reduced serum levels of aspartate aminotransferase and alanine transaminase significantly compared to the control group.24,25 These studies suggest the adjunctive use of melatonin in the treatment of chronic periodontitis. The gene discussed is GPT; the disease is periodontitis.