The public toilets at the Natural History Museum and Heuston Station have tested positive for cocaine residue.
An investigation by Newstalk Breakfast has revealed that 15 bars and five public buildings in Dublin were tested with cocaine-detecting wipes.
The wipe changes to a blue colour if cocaine traces are present. Ten of the bars tested were found to have traces of cocaine.
The cistern, toilet lid, toilet roll holder and any shelves in the toilet were tested.
The results varied in strength - some places showed up small blue dots on the sheets.
But others saw a handprint of blue present on the sheet.
A number of well-known public buildings were found to not have any cocaine present - including Trinity College Dublin and the GPO.
However as the GPO has no public toilets, the team took samples from a number of public desks.
Newstalk radio reporter, Sarah Ruane, said they also tested a Government Department building.
She said: "A Government Department building was the next building we tested and again we went into the toilets here using the cocaine-detection wipes.
"We got the all-clear here so no cocaine detected in our Government Department building."