Synthetic marijuana, which is known as 'Spice' or 'K2', is an herbal mixture sprayed with chemicals that create a high similar to smoking marijuana, according to the National Institute on Drug Abuse.
Advertised as a 'legal' alternative to weed, it's often sold as incense or potpourri. When many states outlawed the drug, manufacturers slightly changed the compound so they were no longer illegal.
It was linked to 11,406 drug-related emergency department visits in 2010, a study by the Substance Abuse and Mental Health Services Administration found. Most were aged 12 to 17.
The first state laws banning synthetic drugs were established in 2010. Now at least 41 states have banned them, but that has not deterred the manufacturers.
'These drug manufacturers slightly change the chemical compound, and it becomes a different substance that's not covered by the law,' said NCSL policy specialist Alison Lawrence.
Common side effects from smoking synthetic marijuana include bloodshot eyes, disturbed perceptions, a change in mood, paranoia, raised blood pressure or hallucinations.