The HSE says it's worried about a potential spike in drug overdoses when nightclubs reopen.
It's warning anyone going out tonight that the strength of substances like MDMA and cocaine is at an all-time high.
People may also have lower tolerance levels so could overdose more easily.
Dr Eamon Keenan, the HSE’s National Clinical Lead for Addiction Services, says club-goers should be aware of the risks:
"The strength of MDMA has increased over the last two years, there's over 300mg in a tablet and maybe people would have been used to tablets with 100mg, so that's a significant rise in potency, and that's what we're worried about."
Meanwhile, the HSE says it's also monitoring reports of students having their drinks spiked.
It happened to six students from Munster Technological University in Tralee Co. Kerry last week.
While police in England are investigating dozens of complaints from women who've been spiked by injection.