They're called "bath salts," but these are not your grandmother's epsom salts or your mom's Calgon: They are synthetic stimulants, usually mephedrone, but sometimes methylenedioxypyrovalerone (MDPV) or its metabolite, pyrovalerone. To avoid detection and control, the products are sold as a powdery substance in small-volume packets labeled as "bath salts" or "plant fertilizer" and marketed with a variety of colorful names, including "Ivory Wave," "Purple Wave," Red Dove," "Blue Silk," "Zoom," "Bloom," "Cloud Nine," "Ocean Snow," "Lunar Wave," "Vanilla Sky," "White Lightning," "Scarface," and "Hurricane Charlie."

Although the packages are marked "not for human ingestion," the products are ingested by swallowing or snorting, and they can cause chest pains, increased blood pressure, increased heart rate, agitation, hallucinations, extreme paranoia, and delusions.

Reports of harm include cases like that of Neil Brown of Fulton, Miss., who slit his face and stomach repeatedly with a skinning knife after ingesting bath salts (Brown survived his injuries), and Cynthia Palmer, a mother of two from Calvert, Ky., who said she hallucinated after snorting bath salts. Kentucky State Police say they found a 2-year-old boy with a head injury lying on the inside edge of I-24 in Marshall County and his mother carrying a 5-year-old child in the median; Palmer had dropped the younger child after stopping her car and attempting to carry both children across the roadway.

"These chemicals act in the brain like stimulant drugs—cocaine substitutes—and present a high abuse and addiction liability," said National Institute on Drug Abuse (NIDA) Director Nora Volkow, M.D., in a message issued in late February about these emerging and dangerous products.

These particular drugs, known as methcathinones, are similar to cathinone, a central nervous system stimulant found in the leaves of the "khat" bush (Catha edulis). Methcathinones are derived in a manner similar to methamphetamines: Ephedrine and pseudoephedrine undergo reduction to yield methamphetamine or oxidation to yield methcathinone. And, like methamphetamines, methcathinones can be readily produced in a makeshift laboratory. The comparisons to cocaine are also inescapable: "Mephedrone appears to be used primarily intranasally and to have comparable abuse potential to cocaine, with more than half of those who use both reporting that mephedrone gives a better quality high," said Adam Winstock, M.B.B.S., and his colleagues in the January Addiction. They reported the results of a cross-sectional anonymous online survey of mephedrone use as part of a larger study exploring patterns of drug use among those associated with the dance music scene.

For the time being, these compounds are legal—and easy to get—in many parts of the United States, although Michigan, North Dakota, Louisiana, and Florida have outlawed them. The Federal Analog Act, part of the Comprehensive Drug Abuse Prevention and Control Act of 1970, allows any chemical "substantially similar" to an illegal drug (in Schedule I or II) to be treated as if it were also in Schedule I or II, but only if it is intended for human consumption, hence the designation on all bath salts that they are "not for human ingestion."

Bath salts are sold online and in drug paraphernalia stores, convenience stores, discount tobacco outlets, gas stations, pawn shops, tattoo parlors, and truck stops, among other locations. They have been slow to arrive in the United States: Sweden, Norway, Denmark, the Netherlands, Finland, Croatia, and Estonia had declared them to be controlled substances by late 2009, and the United Kingdom classified them as Class B drugs under the Misuse of Drugs Act in April 2010. Cathinone-type drugs have been seen in Canada since 2006 and are regulated there under the Controlled Drugs and Substances Act.

"Most new designer drugs are prepared to circumvent existing legislation, to create new drugs with desirable pharmacological properties, and/or to avoid detection through normal testing protocols," explained Chad Maheux, M.Sc., of the Canada Border Services Agency and his colleagues in the December 2010 Microgram Journal, and the methcathinones appear to be doing all of those things successfully. A group of British criminologists, evaluating the rise and subsequent illegalization of mephedrone that occurred in the United Kingdom from 2009 to 2010, have suggested that the popularity of mephedrone has more to do with events in the current drug climate than the drug itself. They blame significantly reduced availability—leading to reduced purity—of cocaine and ecstasy for users' "displacement" to more readily available "legal highs" such as mephedrone and other cathinones.

"It is exactly because users' desire for intoxication is constrained by concerns about availability, purity, legality, and price that mephedrone has risen to its current popularity," according to Fiona Measham, a senior lecturer in criminology at Lancaster University in Lancashire, England, and her colleagues in the March 2010 Drugs and Alcohol Today.

Perhaps the most alarming feature of these designer drugs is the role the Web plays in their rapid appearance and rise in popularity. "The recreational drug market ... is constantly evolving, with the Internet playing an increasingly dominant role," said researchers with the Psychonaut Web Mapping Project, a two-year European Union–funded project (January 2008-December 2009) with the aim of developing a Web-scanning system to identify and categorize novel recreational drugs/psychoactive compounds and new trends in drug use based on information available on the Internet. The researchers presented their findings at the 21st International Harm Reduction Association's Annual Conference in April 2010 in Liverpool, England, where they pointed out that "from a harm-reduction perspective, the rapid rate of diffusion of these new drugs is a challenge for health professionals, as there is often very little, if any, evidence-based literature about the substances available."

NIDA agreed: "We will continue to monitor the situation and promote research on the extent, pharmacology, and consequences of bath salts abuse," said Volkow. "In the meantime, I would like to urge parents, teachers, and the public at large to be aware of the potential dangers associated with the use of these drugs and to exercise a judicious level of vigilance that will help us deal with this problem most effectively."

The "Message From the NIDA Director on ‘Bath Salts’—Emerging and Dangerous Products" is posted at <http://drugabuse.gov/about/welcome/MessageBathSalts211.html>.