There are 70 cases of severe bleeding, including two deaths, linked with synthetic cannabinoids -- often called Spice, K2 or fake weed -- across Chicago and areas in central Illinois.
All of the cases involved unexplained bleeding, such as coughing up blood, blood in the urine, bloody nose or bleeding gums.
On Monday, state health officials reported 56 cases, including those two deaths, who were men in their 20s; one of the deaths was in Chicago and the other in central Illinois. Nine of those cases tested positive for brodifacoum, or rat poison.
"We continue to see cases coming in," said Dr. Allison Arwady, chief medical officer at the Chicago Department of Public Health.
"It's really an emergency in terms of getting this information out to the public," she said. "Experimenting with these substances is just dangerous for your health. We don't know what's in them at the best of times, and right now, we know that what is in them can potentially be life-threatening."
Health officials warn that synthetic cannabinoids can have serious -- and sometimes deadly -- side effects, and anyone who has a reaction such as severe bleeding should call 911 or be taken to the emergency department immediately.
Though 19 of the recent cases were tied to synthetic cannabinoid products in Chicago, contaminated products could be in counties across the state, the Illinois Department of Public Health noted.
There have been six cases in Cook County, two in Kankakee County, 20 in Peoria County, 15 in Tazewell County and one in each of the counties of DuPage, Kane, McLean and Will.
Four other cases are under investigation.
'We strongly urge everyone not to use synthetic cannabinoids'
The department "is continuing to work with local health departments and the Centers for Disease Control and Prevention, along with other partners, to try to identify common products," Dr. Nirav Shah, director of the Illinois Department of Public Health, said in a statement Monday.
"Without more information, IDPH does not know how much contaminated product is circulating or where," he said. "We strongly urge everyone not to use synthetic cannabinoids."
Synthetic cannabinoids, sometimes called "synthetic marijuana" or fake weed, are human-made chemicals that can be either sprayed on dried, shredded plant material and smoked, or sold as liquids to then be vaporized and inhaled in e-cigarettes or other devices.
"There's no such thing as one synthetic cannabinoid. There's hundreds of them, in fact, and even in the setting of this outbreak when we've been interviewing our cases, we've heard of dozens of names that these are going under," Arwady said.
Although these mind-altering chemicals are called cannabinoids, since they are designed to be similar to chemicals found in the marijuana plant, their actual impacts on the brain and body are much more powerful and can include side effects different from those of marijuana.
"They're synthetic, so they're all made in labs. They don't start like a plant like marijuana does," Arwady said.
A study published in the New England Journal of Medicine in 2016 found that one of these chemically altered synthetic cannabinoids was 85 times as potent as tetrahydrocannabinol, or THC, the mind-altering chemical in marijuana.
These products can be toxic, and people who smoke them also can react with rapid heart rate, vomiting, agitation, confusion and hallucinations, according to the CDC. So why would anyone use them?
A few reasons might be that they are easily accessible. They are sold in convenience stores, gas stations, drug paraphernalia shops, novelty stores and even online. And they cost about $10 a packet, Arwady said.
"They also don't show up in urine drug screening in the way that regular marijuana would," she said. "So perhaps somebody who would use marijuana but is concerned about needing to take a drug test for work, for example, might think this is a safe alternative, but it's really not a safe alternative even at the best of times and especially not right now."
The federal government has banned many specific synthetic cannabinoids, and many state and local governments have passed laws targeting other dangerous synthetic cannabinoids.
However, makers of synthetic cannabinoids try to get around those laws by creating products with different ingredients and labeling them "not safe for human consumption" when they may appear like a type of incense or potpourri, according to the CDC.
"They're not regulated," Arwady said.
"The folks who are working to make these in the labs might know the chemicals that have been deemed technically illegal," she said. "They can make small changes in the molecules of what they're making in the lab and try to skirt that illegality."
3 arrested in connection with Illinois outbreak
The US Attorney's Office charged three men with federal drug offenses, accusing them of conspiring to sell synthetic cannabinoids at a Chicago convenience store, in connection with some of the cases.
"We've had to be a little bit creative with the ways that we've gone about identifying patients, making sure we're getting messaging to physicians, and then working with our partners on the law enforcement side to make sure that they're doing what they can to work on the supply side," Arwady said.
When it comes to synthetic cannabinoids, "what we want is for people to absolutely not use them," she said.