Francis, 86, gave no sign that he was about to enter hospital for planned surgery during his general audience in St Peter’s Square, where he was in good spirits, stopped to kiss babies and lingered to chat with newlyweds.
Shortly afterwards, he left the Vatican in a simple white Fiat 500 L for the Catholic-run Gemelli hospital a short drive away and which has a 10th-floor suite reserved for pontiffs.
The surgery, which the Vatican said was scheduled to begin in the early afternoon on Wednesday, is the third hospital stay for Francis since cardinals chose the Argentinian in 2013 as the first Latin American pontiff.
It is the latest in a string of health problems in recent years.
A Vatican source said all of the Pope’s private and general audiences had been cancelled until June 18.
In his 2021 stay there, however, Francis recited the traditional Sunday prayer from a hospital balcony.
A statement, which was unusually detailed by Vatican standards, said he was expected to stay for “a number of days” to allow for “normal post-operation progress and full recovery of his functions”.
It said the operation was necessary to repair a laparocele, a hernia that sometimes forms over a scar usually resulting from a previous surgery.
It is more common in older people and it can also be caused by obesity or weakness of the abdominal wall muscles.
The Pope’s medical team had decided in recent days that surgery was required because the condition was causing painful, intestinal occlusions.
Francis is known to be afraid of the negative effects of general anaesthesia, which are also more common in older people.
The statement said the Pope would undergo a laparotomy, or open abdominal surgery, and that a prosthesis would be used to reconstruct the abdominal wall.
In July 2021 he had part of his colon removed in an operation aimed at addressing a painful bowel condition called diverticulitis.
He said earlier this year that the condition had returned and was affecting his weight.
Francis spent about 40 minutes at the same Roman hospital on Tuesday for what the Vatican said was a “check up,” without disclosing then that it was, in effect a pre-operation visit.
Francis was treated for five days at the same hospital at the end of March with a lung infection and last month skipped audiences for a day due to a fever.
The Pope often uses a wheelchair or a cane to walk because of persistent knee pain.
Last year he did not want to have an operation on his knee because the general anaesthesia for his colon surgery had brought disagreeable side-effects.
Despite his health issues, Francis maintains a busy schedule.
The Vatican announced plans on Saturday for him to visit Mongolia on August 31-September 4, one of the more remote places he has travelled to.
Before that he is due to visit Portugal from August 2-6 to attend the World Youth Day in Lisbon and visit the Shrine of Fatima.
The Vatican on Tuesday released an official schedule for the trip, giving an indication it was confirmed.