Ketamine is an anesthetic known globally both for its potent dissociative properties and potential for abuse. More recently, ketamine demonstrates utility in a variety of disease states such as treatment-resistant depression, status asthmaticus, and acute agitation. In addition, ketamine has been shown to demonstrate various effects at different doses, which adds to its pharmacological benefit. As these new indications continue to come to light, it is important to stay current with the dosing for these indications as well as the adverse effects associated with ketamine's use. This review highlights the history and mechanism of ketamine as well as addressing the use of the different dosing ranges of ketamine.