A woman in her 20s, who was arrested yesterday in connection with a €40,000 drug seizure in Thurles, has been released without charge.
Her arrest followed the search of a house by gardai on Tuesday night where heroin, cannabis and amphetamine were found.
A man in his 30s who was arrested at the scene and remains in custody.
He is being held at Thurles Garda station under Section 2 of the Criminal Justice Act, allowing for his detention for up to seven days.
Separate Garda operations in Roscrea and Thurles in Co Tipperary and Birr in Co Offaly were launched into the activities of suspected drug dealers yesterday.
A number of properties were searched by a team of around 50 gardaí at five locations. The searches in Roscrea and Birr resulted in two arrests.
The investigations come after concerns were expressed in Co Tipperary over increased drug use.
There have been public meetings in Roscrea in the past week in which local people voiced their anger about the impact of the drugs trade on the town.
The attendance was estimated at more than 1,000, in a town with a population of 5,000, with many concerned that recent attacks and suicides in the town were linked to a growing drugs problem, in particular a worsening heroin trade.
A protest was also staged outside the local Garda station in a bid to encourage a firmer response from gardaí.
Garda sources says drugs trade nationally appears to be recovering in line with wider economic conditions.