The Windsor-Essex Community Opioid and Substance Strategy has issued an alert because of a high number of overdoses this week.
Over the past two days, 11 people went to area emergency departments because of overdoses, five were opioid related.
Local Medical Officer of Health Dr. Wajid Ahmed says this is not the first time an alert has been issued.
"We are issuing this alert to the community so that people who are either using the drugs or know people who are using substances, they can be extra careful when they use the substance because there maybe some connection with the possibility of maybe a new dealer," says Ahmed.
Dr. Ahmed adds it's important the residents are aware what's happening in the community.
"We also don't want to sit on that information for to long because this is timely information that needs to go out there and if this is happening right now, people should be aware of it and may take precaution as appropriate," says Ahmed.
The Windsor-Essex County Health Unit says EMS have also administered Naloxone, the drug that reverses an overdose, seven times this week.
- with files from AM800's Kathie McMann