The  removal  of lower third molars is the most common surgical procedure done by oral and maxillo facial surgeons. It is often associated with swelling, pain and trismus as a result of the postoperative inflammatory response, and these can have a serious impact on the patient’s quality of life, as well as having financial consequences.When body tissues are injured the normal physiologic response is inflammation and pain to varying degree. Inflammation occurs after every surgical intervention and should be expected. The most important component of inflammation is vasodilation, which allows cells and mediators entry to the affected area; these are responsible for neutralizing and removing the antigens and the remains of damaged tissue.Corticosteroids  are often used to minimize the post-operative inflammation following surgical removal of mandibular third molar . Mechanism of action of corticosteroid includes inhibition of the enzyme phospholipase A2 , which inhibits the conversion of  phospholipids into arachidonic acid in the cells of the inflamed focus. This will decrease prostaglandin and leukotriene synthesis, therefore reducing the accumulation of neutrophils and thereby reducing inflammation.  Dexamethasone , with its long half-life, potency, and almost pure glucocorticoid activity makes it a safe and effective anti-infammatory drug . Dexamethasone  is usually administered via various routes like Intravenous, Intramuscular and Oral.