The Missouri House has approved new legislation taking aim at synthetic drugs.
The measure would add several specific substances to what is considered synthetic marijuana. It passed the House 139-4 on Thursday and now goes to the state Senate.
Missouri legislators previously have targeted synthetic drugs. The Legislature in 2010 barred a substance known as K2 and sold as incense.
A year later, the definition of marijuana in state drug laws was expanded to cover synthetics. The 2011 measure also barred substances marketed as incense or "bath salts" that mimic the effects of cocaine and marijuana.