The Waterford athlete has been "hit with a bad bout of gastroenteritis”
Thomas Barr has been forced to pull out of the World Athletics Championships in London due to a vomiting bug.
The Waterford athlete was due to race in the 400m hurdles semi-finals this evening.
In a statement this morning, the Ferrybank star said he is “gutted to have to withdraw.”
“I wasn't feeling great yesterday evening and later in the night I was hit with a bad bout of gastroenteritis,” he said.
"My whole year has been focused on the World Championships.
“The support yesterday was just brilliant and to not be able to go out and compete today for Ireland is beyond disappointing."
Barr finished fifth in qualifying yesterday, coming in at 49.79 seconds.
He was pushed up to fourth after Virgin Islands Kyron McMaster was disqualified for a hurdle infringement.
Barr would have qualified as a faster loser regardless of the disqualification.