Recreational drug use patterns change constantly, making it imperative that clinicians continuously update their knowledge about current trends of use and abuse. Particularly challenging are substances that have been described as nontraditional, emerging, and Web based, which have increased significantly in the last 2 years. This report reviews the epidemiology, pharmacology, clinical presentation, and toxicity as well as recommended management for 2 classes of emerging substances of abuse: herbal marijuana alternatives (eg, synthetic cannabinoids) and "bath salts" (eg, substituted cathinones). A brief review of the development of the regulation of these substances highlights the challenges associated with surveillance and subsequent enforcement of laws for emerging nontraditional substances of abuse. © 2012 Elsevier Inc.