WASHINTON (CNN) -- It's a drug that's already banned in more than 40 states. Now, White House Drug Czar Gil Kerlikowske is talking about a federal ban on so-called "bath salts."

That's a substance sold over-the-counter at gas stations and convenience stores. When taken as drugs, the chemicals in these bath salts are believed to cause paranoia, hallucinations and even violent behavior.

Office of Natl. Drug Control Policy director Gil Kerlikowske says, "One of the things that we're really hopeful is new federal legislation that will ban this. Many of the states have already banned it. But what happens is the people that sell and market this, who are truly bottom feeders, change the chemical compilation and then are able to skirt the law. But, hopefully, federal legislation is going to work to stop that."

"Bath salts" is a catch-all name for synthetic stimulants meant to mimic the effects of illegal drugs like meth, cocaine and LSD.