La Crosse County has sent out an alert, warning of several local overdoses apparently resulting from a potent batch of heroin.
Medical examiner Tim Candahl said at least six overdoses have been reported in La Crosse County since Wednesday, with similar reports from neighboring counties.
No deaths reportedly have resulted from the drug use yet.
Candahl added that the substance mixed with heroin has not been identified, but he suspects that it may be fentanyl.
The examiner says people who have been using heroin should keep Narcan available, to stop an overdose.