Dolores O’Riordan gave the Gardai cause for concern after they reportedly heard her singing in her cell at the station in Shannon.
The Cranberries frontwoman was detained by Irish officers after she allegedly assaulted an air hostess following a flight from JFK New York.
She also allegedly assaulted an arresting Garda.
However, after she spent three hours behind bars at the Shannon Garda Station in the early hours of yesterday morning, officers feared for her well-being and called a doctor to assess her health.
O'Riordan, 43, was later taken to the University Hospital Limerick (UHL) at 10am where she was seen by medical professionals, before being released into the care of her mother Eileen that afternoon, the Irish Independent reports.
The former Voice of Ireland singer will now wait to hear whether the Director of Public Prosecutions (DPP) will charge her in relation to a Section 3 assault.
The O'Riordan family have thus far declined to comment.
The alleged incident resulted in one flight attendant receiving treatment for an injury to her foot.
One of the two Gardai called to arrest O'Riordan was also allegedly headbutted by the singer after they were called to meet the EI-110 flight shortly before 5am.
“I was in sitting in economy with my husband and heard the commotion in business class,” an eye witness said. “There was a woman standing up and she was shouting. It was about 20 minutes before landing.
“It quietened down for a while and after landing it started again… When the front door was opened, some people in hi-vis jackets got on and the curtains between business and economy were closed. We could still hear the commotion.
“The curtains were opened a few times and at one stage we saw the woman thumping the ceiling of the plane. She was roaring at the cabin crew and at one stage I heard her say ‘I pay my taxes’.”
A spokesperson for The Cranberries is yet to respond to a request for comment.