Gardaí are not monitoring drug surrender bins at Electric Picnic, according to the HSE.
The Health Service Executive is running a pilot drug surrender programme at the festival in Stradbally, Laois, as it returns after a two-year absence.
The HSE is urging anyone who feels unwell after taking a substance to hand it over to be tested.
The drugs will be tested immediately, and if a particularly dangerous strain is identified, a message will be announced at the festival.
Eamonn Keenan, HSE national lead for addiction services, fears people will hesitate to come forward:
"I would like to reassure everybody that the Gardaí are not going to be in the medical tent. They're not going to be in the tent unless there's a public order offence. They're not monitoring these tents so rest assured people can attend these medical tents."
