NHS Dumfries and Galloway’s specialist drug and alcohol service started spreading the word on Tuesday.
And they revealed that: “Repeated medical interventions have already been needed” as a result.
They appealed for people to take care and look out for those who may be vulnerable, and to call 999 if in doubt.
In a statement on social media, the service said: “We have had notification of a very strong batch of heroin, on sale in the region since Friday 7th October requiring medical interventions.
“Remember . . . never use alone, start low and go slow and always have a Naloxone kit available. Call 999 for an ambulance if you think someone is experiencing an overdose.”