(CNN) Synthetic cannabinoids -- often called Spice, K2 or fake weed -- have been tied to 56 cases of severe bleeding , including two deaths, across Chicago and areas in central Illinois.

All of the cases required hospitalization related to coughing up blood, blood in the urine, bloody nose, bleeding gums and other symptoms. Nine of the cases tested positive for brodifacoum, or rat poison, according to a statement from the Illinois Department of Public Health on Monday.

Now, state officials are working to identify any common synthetic cannabinoid products related to those cases and to determine where the products were obtained.

There are still many questions about the illnesses; officials are not aware what exactly caused the drug contamination, but investigators and toxicologists are continuing to evaluate.

"This is the first time we've seen an outbreak of this magnitude in the area," Melaney Arnold, a spokeswoman for the Illinois Department of Public Health, said Monday.

"We're working with numerous different partners across the city and state as we investigate this outbreak," she said.

Synthetic cannabinoids are sold in convenience stores, gas stations, drug paraphernalia shops, novelty stores and even online.

Health officials warn that anyone who has a reaction to synthetic cannabinoids immediately should call 911 or be taken to an emergency department.

'There could be additional deaths coming'

"We continue to see the number of cases rise," Dr. Nirav Shah, director of the Illinois Department of Public Health , said in the statement.

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," he said. "Without more information, IDPH does not know how much contaminated product is circulating or where. We strongly urge everyone not to use synthetic cannabinoids."

Though 17 of the recent cases were tied to synthetic cannabinoid products in Chicago, contaminated products could be statewide, the Department of Public Health noted

There also were five cases in Cook County, two in Kankakee County, 14 in Peoria County, 12 in Tazewell County and one in each of the counties of DuPage, Kane, McLean and Will. Two other cases are under investigation.

One of the deaths was in Chicago and the other in central Illinois.

Officials had never before seen a death in Chicago related to fake weed, Arnold said.

"There could be additional deaths coming; it is difficult to say," she added. "We're doing whatever we can with regards to outreach to notify any who may be impacted by this outbreak."

What is fake weed?

This isn't the first time a region of the United States has seen an outbreak of health problems tied to synthetic cannabinoids.

Last year, 102 people in Lancaster County, Pennsylvania , overdosed on synthetic marijuana within three days. None of those cases was fatal.

In 2016, 33 people in Brooklyn were made ill from suspected overdoses of synthetic pot.

During that time, physicians treated 456 patients total for synthetic cannabinoid intoxications.

Synthetic cannabinoids, or fake weed , are human-made chemicals that can be sprinkled on dried, shredded plant material and smoked, or can be consumed as vaporized liquids inhaled through an e-cigarette or other device.

These mind-altering chemicals are called cannabinoids, since they are similar to the chemicals found in marijuana, though they can cause serious side effects that are different from those of marijuana.

One study of a synthetic cannabinoid found that it was 85 times as potent as tetrahydrocannabinol, or THC, the mind-altering chemical in marijuana. That study was published in the New England Journal of Medicine in 2016.

JUST WATCHED How synthetic drugs are killing kids Replay More Videos ... MUST WATCH How synthetic drugs are killing kids 04:20

People who smoke synthetic cannabinoids can have rapid heart rate, vomiting, agitation, confusion and hallucinations, according to the CDC.

In the past few years, doctors have become familiar with the health outcomes people can face when they are exposed to synthetic cannabinoids, said Dr. Patrick Lank, an emergency physician and assistant professor of emergency medicine at the Northwestern University Feinberg School of Medicine in Illinois.

Follow CNN Health on Facebook and Twitter See the latest news and share your comments with CNN Health on Facebook and Twitter.

"They include things like seizures, heart attack, kidney failure," said Lank, who was not involved in the recent synthetic cannabinoid cases.

"What's happening in Illinois is different, and these are bleeding complications. Why they're happening? We're still uncertain," he said. "We don't know if the supply of synthetic cannabinoids in Illinois and the Chicago area have been tainted by someone with brodifacoum, or rat poison. Or if this is potentially a new side effect of a new synthetic cannabinoid."