This chapter examines the role of ketamine in the management of prehospital and hospital emergencies, with a focus on its efficacy as an induction agent for intubating critically ill patients. Appropriate pain therapy is associated with improved patient outcomes after severe trauma, but pain is often not controlled. This is particularly relevant in unstable patients, where cardiorespiratory depressant agents are avoided due to the risk of further destabilizing the patient and creating other adverse conditions. A low to sub-anesthetic dose of ketamine is a safe and effective analgesic in trauma care. It offers an alternative to opioids or can be combined with opioids, providing enhanced analgesia while avoiding opioid-related respiratory depression. At anesthetic dose, ketamine is the preferred choice for induction of anesthesia in rapid sequence intubation. Ketamine is a highly effective analgesic and sedative adjunct in post-intubation sedation and analgesia, as well as for procedural sedation. It may be beneficial to use ketamine in trauma patients experiencing acute agitation and delirium. In brain trauma, ketamine can prevent secondary injuries by increasing the cerebral perfusion pressure and inducing neuroprotective effects. With appropriate expertise, ketamine can be used without or with minimal psychoactive events.