QUEEN Elizabeth II has been hospitalised over an apparent stomach infection that has ailed her for days, Buckingham Palace said Sunday, news.com has reported.

The illness has forced her to cancel a visit to Rome and other engagements as she recovers.

The palace said the 86-year-old British monarch had experienced symptoms of gastroenteritis and was being examined at London's King Edward VII Hospital. "As a precaution, all official engagements for this week will regrettably be either postponed or cancelled," the palace said in a statement.

Elizabeth's two-day trip to Rome had been planned to start Wednesday. A palace spokeswoman said the trip may be "reinstated" at a later date.

The symptoms of gastroenteritis - vomiting and diarrhea - usually pass after one or two days, although they can be more severe in older or otherwise vulnerable people. Dehydration is a common complication.

The illness was first announced Friday, and Elizabeth had to cancel a visit Swansea, Wales, on Saturday to present leeks - a national symbol - to soldiers of the Royal Welsh Regiment in honor of Wales' national day, St. David's Day. She instead spent the day trying to recover at Windsor Castle, but appears to have had trouble kicking the bug.

A doctor not involved in the queen's treatment said that if medical officials determined she had lost too much fluid, she could be rehydrated intravenously.

"I suspect that she's being assessed and that it'll be a relatively uncomplicated treatment," Dr Chaand Nagpaul told Sky News television. "It is very much about ensuring that the body receives the fluid it needs."

Elizabeth is one of Britain's longest-reigning monarchs and has rarely let ill health get in the way of her still-busy schedule.

About five months ago, she cancelled an engagement due to a bad back. The spokeswoman, who demanded anonymity because palace rules do not let her go on the record, said the last time Elizabeth was hospitalised was in 2003.

The queen has undertaken a number of engagements over the past week. On Tuesday, she met the new archbishop of Canterbury, Justin Welby, at Buckingham Palace, and on Thursday she presented a host of Olympic stars, including track and field star Jessica Ennis, with honors during an investiture ceremony.

Ingrid Seward, the editor of the Britain's Majesty Magazine, said that the queen "probably agreed to be hospitalised in order to get better quickly."

"Everybody will want to be wishing her a speedy recovery," she told Sky.