Wellington-Dufferin-Guelph Public Health is urging caution for drug users as there has been at least 22 drug poisonings and two deaths since February 14th in the area.
In these incidents, light green and beige fentanyl are the colours of concern.
Public health says the current unregulated drug supply is unpredictably potent and contains other substances.
Public says those who are taking drugs should carry naloxone which is available for free with public health, at local pharmacies and the downtown library in Guelph.
If you do intend to use, to start low and go slow and are reminded of the Good Samaritan Drug Overdose Act which protects those at the scene of a drug poisoning from simple possession charges with 911 is called.