In oral and maxillofacial surgery, local anesthesia is used in exodontia, minor oral surgical procedures and in some major surgical procedures.Without vasoconstrictors local anesthetic agents can produce vasodilatation and increases rate of absorption of local anesthetics from injection site. Vasoconstrictors are added to local anesthesia to reduce bleeding from surgical site and to increase the duration of action of local anesthetics. Clonidine has been widely used, for a variety of purposes including withdrawing from long term abuse of drugs or alcohol, as well as to reduce perioperative stress in patients who are at risk of perioperative ischaemia. Clonidine has also proved to be a clinically useful adjunct in clinical anesthetic practice as well as in chronic pain therapy.