In the last five years, a new wave of designer drugs has flooded the United States. Usually marketed as “legal highs,” these compounds have become one of the latest challenges facing the criminal justice system. While the addition of designer drugs to the market is nothing new, the Internet has played an unprecedented role in their recent proliferation. Not only are these products a challenge for law enforcement, they also present a unique set of challenges to the forensic science community. There are three main types of designer drugs predominant in today’s market: synthetic cannabinoids, substituted cathinones, and hallucinogenic phenethylamines.