Chicago emergency crews responded to 35 suspected opioid overdose cases Tuesday, nearly twice the city’s daily average of 19, prompting the Chicago Department of Public Health to issue a warning about a possible spike in overdoses. The 35 suspected opioid-related EMS responses were concentrated in South Shore and Chatham, CDPH said.
The spike does not mean 35 people died or that all 35 cases have been confirmed as opioid overdoses, but the Overdose Detection Mapping Application Program, a real-time surveillance system used to identify possible overdose clusters, identified the cluster.
CDPH urged people to carry naloxone, commonly known as NARCAN, the medication that can rapidly reverse an opioid overdose. Officials also delivered a blunt warning about ingesting counterfeit or other pills not prescribed by a doctor and dispensed by a pharmacy.
The department did not identify a specific drug or source as the cause of Tuesday’s increase. However, fentanyl, a synthetic opioid that is up to 50 times more potent than heroin, has become a leading driver of overdose deaths in the United States. While it was once most commonly found mixed into heroin, it is now frequently detected in cocaine, counterfeit prescription pills, methamphetamine, and other illicit drugs, often without users’ knowledge.
In recent years, authorities have also encountered even more potent synthetic opioids, including nitazenes, which can be several times stronger than fentanyl. Health officials monitor short-term overdose spikes because they can signal changes in the local drug supply.
Chicago’s opioid overdose death toll has also declined from its peak. A joint Cook County and Chicago health department report released in June said opioid overdose deaths in Chicago fell substantially in 2024, with preliminary data showing another decline in 2025.
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