The HSE has issued a warning to heroin users to avoid buying new batches of the drug.
There's been a significant increase in the number of overdoses from the substance in the City, with 20 being reported in just 24 hours.
The HSE says it's monitoring the situation and is awaiting analytical confirmation on the matter.
Nicki Killeen, Emerging Drug Trend Project Manager with the HSE, says they're aware of a rising issue across the city, and has advised drug users to be careful.
"It's obviously very important for us at this moment in time, while we investigate what's actually going on, on the ground, that we highlight that there is an extra risk associated with this market.
"So, we want to rmeind people taht there's extra risks at this time. So, we want to rmeind people to try and avoid buying any drugs that might be new. So, drugs that are sold as new drugs, new types of drugs, new batches of drugs.
"We're encouraging people to go into services to discuss their use, to try and access a naloxone, which is an opiate reversing drug, or treatment and to discuss harm reduction."
Ms. Killeen adds they have reason to believe the number of overdoses has reached 20, base don medical callouts and reports to the HSE.
Be aware. There is a bad batch of heroin in Dublin. There have been 13 overdoses today. Please let people know. If you're going to use dont use on your own. If someone overdoses diall 999. pic.twitter.com/D18PtnENzC
— Cllr. Daithí Doolan (@DaithiDoolan) November 9, 2023
Dublin City Councillor, Daithí Doolan, has also warned heroin user to be cautious of what they are buying and using at this time.
It's understood the issue is confined to the City Centre, and the HSE is investigating the matter.