Anesthesia is essential for the practice of surgery. Since its beginning in 1842 it has evolved in to a recognized specialty providing continuous improvement in patient care.Before the discovery of inhalational agents pain was considered or believed to be an inevitable outcome of surgery. Today, major surgery without adequate anesthesia would be unthinkable, and probably constitute grounds for malpractice litigation. Recent development dating back only 160 years. Anesthetists receive lives of patients in her/ his hands, It is a duty to administer the safest anesthetic possible, to protect the patient and to give full attention for the anesthetized patient.To carry out the responsibility, every anesthetist needs a foundation of medical science and understand the principles of anesthesia. A sound knowledge of physiology and pharmacology is essential, together with an understanding of impacts brought about by illness or injury.