DENVER - Eight more cases of bad reactions to synthetic marijuana sold as incense have been reported the University of Colorado Hospital.
Half of the patients were admitted Tuesday night and the other half were brought in Wednesday.
They had bad reactions that included hallucination, disorientation and behavior that can be violent to themselves or others.
University has seen about 40 patients so far in the latest wave, which doctors said came after about a year of relative quiet from the synthetic drugs. They are often sold under brand names or street names like Black Mamba , Spice or K2.
The drugs are illegal in Colorado but chemists have responded by changing the chemical molecules in the product so that is outside the law. As a result, doctors don't know for sure what is making the new patients react.
"It's pretty clear that there's some very bad stuff out there right now," said Dr. Kennon Heard, a medical toxicologist and UCH.
"Patients come in and have no gag reflex and are not breathing on their own," said Amanda Puhal, charge nurse at UCH. "And we have to put a tube down their throat to breathe for them."
"They are hallucinating, they are very much not themselves," said Dr. Jeffrey Sankoff, an emergency department physician at Denver Health. "The cannabinoid itself is not dangerous. The issue is that it's been contaminated or altered with other substances."
Doctors said packages brought in by the most recent patients included "Sexy Monkey," "Crazy Monkey" and "Botanical Sachet."
While the packaging often calls these spices "incense" and says "not for human consumption," some people still smoke it.
Officials with the Rocky Mountain Poison Control Center told 7NEWS most of the drugs have not been tested on humans and were never meant to be ingested.
The substance was created in medical labs by a Clemson University researcher as a way to study the effects of marijuana on lab animals. It has a different molecular structure than marijuana, but was designed to stimulate the same receptors, according to the RMPCC.