Gardaí arrested a man with a gun at the emergency department of Our Lady of Lourdes Hospital in Drogheda over the weekend.
The man, believed to be in his 30s and from Drogheda, had gone to the hospital for treatment on Saturday afternoon.
While in the emergency department, he was found to have a gun on him along with a number of rounds of ammunition and a small amount of cannabis resin.
Gardaí were called at about 4pm.
The man was arrested under section 30 of the Offences Against the State Act. He was released without charge on Sunday afternoon.
Gardaí said a file will be prepared for the Director of Public Prosecutions.
It is understood that no staff or members of the public were threatened during the incident.
The suspected firearm and ammunition have been sent for ballistic and forensic examination. The investigation is ongoing.