Oxygen is an element indispensible for life, can under certain situation have deleterious effect on the human body. Most of the potentially harmful effect of oxygen are due to the formation and activity of a number of compounds known as Reactive oxygen species. There is increasing body of evidence available to implicate reactive oxygen species in the pathogenesis of a variety of inflammatory disorders of which periodontal disease is no exception. Lycopene is a natural effective antioxidant. It exhibits highest physical quenching rate with singlet oxygen and three fold more effective than beta carotene in preventing cell death. Many chemotherapeutic agents used in periodontics in addition to their antiseptic properties are known to have an antioxidative activity against spontaneous oxidation. Modulation of free radical production seems to be essential for the inhibition of tissue destruction and treatment with drugs that block the production of free reactive oxygen species or blocks its effect might be therapeutically valuable Antioxidants may be regarded as those substances which when present at low concentration.