Background and Objectives: Impacted third molar surgery is one of the most common procedures performed by maxillofacial surgeons in the outpatient setting. Since the region of surgery is highly vascularized and constituted mostly by loose connective tissue that contains blood and lymph vessels, a series of functional and structural alterations occur after extraction which is expressed as pain, swelling and trismus. These sequelae can have a serious impact on the patient's quality of life; therefore, a reduction of postoperative complications seems a logical goal, particularly if healing is not compromised. Method:A hospital-based case-control study with a study population of 50 patients was done to assess the efcacy of submucosal injection of 8mg dexamethasone on reducing the post-operative sequelae such as oedema, pain and trismus following surgical removal of impacted third molars. The study was conducted in patients with bilaterally impacted mandibular third molars where one side is randomly selected and 8mg dexamethasone is administered submucosally and the other side is selected as control. All the patients selected for the study were followed up on rst, third and seventh post-operative day. Result: The submucosal injection of dexamethasone showed signicant improvement in oedema and trismus on all postoperative days but decrease in postoperative pain was not signicant on rst and third days but signicant on seventh day. Submucosal injection of dexamethasone 8 mg is an effective therapeutic strategy for improving the quality of life after surgical removal of impacted lower third molars.