An influx of highly hallucinogenic, potentially lethal but -- in most states -- fully legal drugs sold as "bath salts" has law enforcement and drug abuse experts very concerned.

According to Mark Ryan, director of the Louisiana Poison Center, in the first month of 2011, there have already been 248 bath salts-linked calls nationwide from at least 25 states, compared to 234 calls during the whole of 2010.

The $20 packets are available in corner stores, truck stops and on the Internet, and marketed as bath salts or sometimes plant food and come with the (often-ignored) disclaimer, "not for human consumption." They're not subject to regulation even though they contain various potent chemicals, including mephedrone, which is a stimulant.

"It's a derivative that's very similar to amphetamines, and its side effects are largely the same side effects we see with amphetamines in large dose," said Jeffrey Baldwin, professor of pharmacy practice and pediatrics at the University of Nebraska Medical Center in Omaha, which seems not to have experienced this scourge -- at least not yet. "[Those side effects] would be increased heart rate and blood pressure, not sleeping, not eating and eventually becoming paranoid."

The "salts" come with gentle-sounding names like Ivory Wave and Vanilla Sky and are typically snorted, smoked, injected and even mixed with water as a beverage.

"If you take the very worst of some of the other drugs -- LSD and Ecstasy with their hallucinogenic-delusional type properties, PCP with extreme agitation, superhuman strength and combativeness, as well as the stimulant properties of cocaine and meth -- if you take all the worst of those and put them all together this is what you get. It's ugly," added Ryan, who recounted some harrowing stories.

"The psychosis is impressive," he said.

One man barricaded himself in an attic with a rifle, Ryan said, vowing to "kill the monsters before they kill me," while another user vowed to remove their own liver with a mechanical pencil.

The products have also been linked to suicides, not to mention hospitalizations, and on Tuesday investigators confirmed the presence of bath salt drugs in the blood of a man who killed a sheriff's deputy in Tippah County, Miss., ABC News reported.

Once an addled user gets to the emergency room, they're not controllable with normal sedatives such as valium, even in high doses, Ryan noted.

And when doctors try to wean patients off stronger sedatives or even antipsychotic medications, they just become uncontrollable again. "The longest I heard was someone who was sedated for 12 days and the psychosis came right back," Ryan said. "The huge concern is the possibility that some of these effects could be permanent. We don't know because we've never tested it on humans."

At least with older drugs, sedation works and the patient returns to "normal," at least until they hit the streets again.

Also worrisome is the fact that while all of the products "have the same basic chemical structure," small changes in the chemical composition give you different side effects, which clinicians then have to learn how to deal with.