The oxidative stress results because of the disturbance in systemic equilibrium of the oxidants and antioxidants. However, when there is increase in the generation of the free radicals such as reactive oxygen and nitrogen species (ROS and RNS respectively), then there is a shift in this systemic equilibrium. Various environmental and lifestyle factors such as pollutants, alcohol consumption, smoking, poor diet and other adverse habits contribute towards the oxidative stress. Oxidative stress can affect systemically (the whole body) as well as locally (in oral soft tissues).Various recent literatures have shown that the oxidative stress and inflammation are predisposing factors for various chronic illnesses, like atherosclerosis, rheumatoid arthritis, diabetes and periodontitis