They may be legal but experts say they can still kill.

Synthetic drugs seem to be all the rage right now and Lehigh Valley Hospital's emergency room is reporting a spike in patients seeking help.

Bath Salts, K2, and Salvia, are just some of the names of synthetic drugs out there right now.

Lehigh Valley Hospital Toxicologists tell 69 News the highs people get from synthetic amphetamines and marijuana are not as high as the real thing but the side effects are the same.

"The euphoria is not comparable to X or other amphetamines or cocaine," said Dr. Matthew Cook. "You get the other effects the high blood pressure and agitation but not the euphoria."

Lehigh Valley Hospital's Emergency Room has seen its share of synthetic drug users in the last year or so.

"Bath salts have become pretty common place to the point that toxicology service doesn't get many calls about it anymore," said Dr. Cook.

Dr. Matthew Cook says that when people first started coming in to the ER high on synthetic drugs the doctors need help from toxicologists to treat patients now it happens so frequently.

"Doctors in the ER are more familiar with it and they know how to deal with it," he said.

They may not be illegal like the drugs that they are meant to emulate but Dr. Cook says the side effects are just as dangerous.

"They produce a similar clinical effect as amphetamines which is rapid heart rate, elevated blood pressure, sweaty agitated anxious," said Dr. Cook.

Worst case scenario is seizures and hypothermia.

In most cases there isn't much that doctors can do for someone high on these synthetic drugs.

"Usually it just needs to run it's course," Cook said.

Like any other drug, synthetic drugs can be addictive but doctors say that they're even more dangerous because no one really knows exactly what's in them.