Per the BBC, the 61-year-old Gibb was supposed to play a series of gigs in such cities as Säo Paolo, Curitiba and Brasilia but after being stricken Sunday morning and taken by ambulance to a nearby medical center, his doctors advised him not to travel.
"We are not sure what's wrong with him at this stage and are worried," a rep for the Grammy-winning "Stayin' Alive" singer told the BBC.
Gibb has battled digestive problems before. Last year, during a tour stop in Belgium, he underwent emergency surgery for a blocked intestine, had part of his intestine removed, and was given a clean bill of health. With the onset of this new malady, physicians are now trying to determine if there's a connection with the prior operation.
"We don't know if it is a recurrence of the previous problem or if it is something else entirely," his publicist added.
Get well soon, mate.