Synthetic cannabis

Synthetic cannabis (synthetic marijuana) is a type of designer drug made from chemicals sprayed onto herbs. Synthetic cannabis is often called K2, Spice, or fake weed. "Synthetic" means "man-made"; "Cannabis" is the plant that marijuana is made from. 
Synthetic cannabis is not really man-made marijuana. It has no marijuana, and no chemicals from the "Cannabis" plant, in it. Instead, it is sprayed with man-made chemicals called "cannabinoids." In the brain, they act like the chemicals in real marijuana (like THC). Because of this, they can make a person feel "high" the same way real marijuana can.
Safety.
Medical research has shown that synthetic cannabis is much more dangerous than regular marijuana. For example, one research study found that people who used synthetic cannabis were 30 times more likely to get emergency medical treatment than people who used regular marijuana. 
Synthetic cannabinoids can also cause much more serious symptoms and health problems than regular marijuana. These problems can include:
Research, and the experiences of people who try to stop taking synthetic cannabis, show that it causes addiction and withdrawal symptoms in some people.
Professor John W. Huffman, who first created many of the chemicals used in synthetic cannabis, has said: "People who use it are idiots. You don't know what it's going to do to you."
Legal issues.
Synthetic cannabis has had a complicated legal history. Its makers have used many different strategies to keep their products from being illegal.
For example, synthetic cannabis is often sold in packages that call it "herbal incense." Most of the packages also have a warning label that says "Not for human consumption" (not for humans to put into their bodies). By doing these things, companies that make synthetic cannabis can say that they are not selling drugs, and it is not their fault if people ignore their warning label.
It has also been difficult for states and countries to make synthetic cannabis illegal because there are so many different cannabinoids. For example, in 2009, the United Kingdom made all the cannabinoids that existed illegal. However, scientists quickly created new versions of cannabinoids, which were not listed as illegal in the U.K.'s laws. Like many other countries, the United Kingdom has tried to ban every new cannabinoid as soon as it is created, but new ones are made all the time.
Most countries in Europe, and a few countries in Asia, have made some or all synthetic cannabinoids illegal.
United States.
Before 2010, the United States Drug Enforcement Administration (DEA) had made some of the cannabinoids used in synthetic marijuana illegal in the U.S. Other cannabinoids were not illegal. Some states passed laws on their own, to make synthetic cannabis illegal in their states. However, before 2010, not all cannabinoids were illegal in the United States.
On June 6, 2010, a teenager from Iowa named David Mitchell Rozga killed himself. His friends said they and Rozga had smoked synthetic cannabis about an hour before he shot himself. Rozga's suicide, and the idea that it might have been caused by synthetic cannabis, was reported in newspapers and media all over the world.
After Rozga's suicide, the DEA used "emergency powers" to make five cannabinoids often found in synthetic marijuana illegal. Also, after the suicide, United States Senator Chuck Grassley suggested a law called the "David Mitchell Rozga Act." This law would make using or selling synthetic cannabis illegal. The law was passed by the United States Congress in June 2011. 
On July 10, 2012, President Barack Obama signed the Synthetic Drug Abuse Prevention Act of 2012 into law. It made the most common chemicals used in synthetic marijuana illegal.