Oral cancer studies showed that manoalide increases ROS [5,10], but there is no proof that antioxidant enzyme proteins change, and we are the first to find that manoalide-induced antioxidant enzyme protein (oxidative stress defense enzymes: catalase, SOD1, and TRX) decreased and the mitochondrial antioxidant enzyme SOD2 increased in OS cells. The gene discussed is SOD2; the disease is lip and oral cavity carcinoma.