This chapter discusses perioperative assessment and drugs antibiotics, analgesics, others, a process in which patients and physicians are interdependent, aimed at enhancing the outcome from a surgical procedure. In this process, it is important for the anesthesiologist to know about these drugs because they can adversely affect the course of anesthesia. A detailed knowledge of mono-amine oxidase inhibitors (MAOIS), phenothiazine derivatives, steroid therapy, ace inhibitors, calcium channel blockers, and angina prophylaxis drugs, is presented. Severely pre-eclamptic patient should not be rushed unprepared into the OT for emergency cesarean section in an effort to prevent convulsions. Also, operations should be cancelled in the circumstances such as due to inadequate preparation and due to risk arising from the poor condition of the patient. Sometimes premedication is given for specific therapeutic effects such as transdermal glyceryl nitrate patches for angina patients and pre-operative steroids for patients who received steroids in the preceding twelve months.