Prince Philip, Duke of Edinburgh, was admitted to a Scottish hospital with a recurrence of the bladder infection he suffered earlier this summer, Buckingham Palace said Wednesday.
Palace officials said Queen Elizabeth II's husband would likely stay in the hospital for a few days for investigation and treatment.
The 91-year-old royal consort was hospitalized for five days in June with a bladder infection that may have been aggravated by his prolonged appearance at a rainy flotilla pageant marking the queen's 60-year reign.
Philip was taken from the royal family's Balmoral estate in Scotland to the Aberdeen Royal Infirmary on the advice of his physician.
The palace said he traveled the 40 miles (64 kilometers) to the hospital by road.
Philip resumed royal duties after recovering from his bladder infection in June, attending the opening ceremony of the Olympics on July 27, watching his granddaughter Zara Phillips take part in Olympic equestrian competition two days later and carrying out engagements on the Isle of Wight on Monday. He has looked well at recent events despite his advancing years.
He was diagnosed with heart disease in December after experiencing chest pains that required him to spend Christmas at a hospital. He underwent a successful coronary stent procedure and seemed to recover well, resuming a full schedule within several weeks.
Philip is a former naval officer who married the queen in 1947. His health remained robust through his 80s, but he has appeared frailer in recent years.
When he turned 90, he said he was "winding down," and he has cut back on official duties. But he still carries out some engagements, both with his wife and on his own.