The 91-year Duke of Edinburgh was taken to Aberdeen Royal Infirmary where he is expected to stay for a few days for investigation and treatment.
Philip was hospitalized for five days in June with a bladder infection, causing him to miss some of the events of the Queen's Diamond Jubilee celebration.
He also spent four nights in hospital over Christmas after suffering chest pains. He was diagnosed with heart disease and had a coronary stent procedure.
While Philip has cut back on his activities in recent years, he is still making appearances with the Queen and on his own. He was on the Isle of Wight on Monday. He also escorted the Queen at the opening ceremonies of the Olympic Games in London on July 27.
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.
Philip, a former naval officer, married the Queen in 1947. For the most part, his health remained robust but he has appeared more frail 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.