Anaesthesia is uniquely positioned at the crossroads between medicine and surgery and is pertinent in delivering perioperative medicine and emergency care throughout the hospital. The practice of anaesthesia is based on the principles of physiology and pharmacology. Since anaesthesia is one of the largest speciality groups in secondary care, a solid understanding of this field is highly relevant. This chapter reviews the main anaesthetic drug groups prescribed in anaesthetics, including intravenous and inhaled anaesthetics agents as well as neuromuscular blocking agents.