Synthetic marijuana use has increased significantly since 2008 among young adults in the United States, as have adverse reactions to it, leading to a dramatic increase in emergency department visits. However, much of the research conducted on it has been case studies, which report detrimental symptoms on an individual basis. Only a limited number of studies aim to better understand the larger parameters of this epidemic to assist health care providers and policy makers, including early detection, intervention, and adequate treatment. In addition, there has been limited critical review of this substance to help health care professionals educate the public about the negative health effects of using this drug. This article explores the critical reviews of synthetic marijuana, also commonly known as “K2” and “Spice,” synthesizing information from literature reviews, case studies, media information, and government websites. Findings were organized by synthetic marijuana's history, description, adverse reactions including withdrawal symptoms and death incidents, detection screening, treatment, and legislative issues. Health care providers need to understand the detrimental effects of this illicit and harmful substance to both the body and mind and sometimes irreversible damage caused to individuals who consume it. Policy makers, the public, and affected individuals and their family members need to be educated as well.