LONDON — Queen Elizabeth II on Monday left the London hospital where she had been admitted a day earlier after suffering from symptoms of gastroenteritis.
Television footage showed the 86-year-old monarch wearing a bright red coat and smiling as she left King Edward VII's hospital and got into a waiting limousine.
A spokesman had said earlier that she was in "good spirits" and that she had been admitted as a "precaution." But since it was the first time the queen had spent the night in hospital in 10 years, questions were raised about her general health.
She first fell ill on Friday and canceled her attendance at a military celebration in Wales marking the country's national day at the weekend.
She was well enough on Sunday to award a medal to an employee at Windsor for her long service and took her car rather than an ambulance to the hospital in London.
"This is a very common problem that most people will have had at some point in their lives, but it is very rare to be hospitalized for it," said consultant gastroenterologist Dr. Anton Emmanuel.
The queen already had canceled her engagements for the week, including a planned two-day trip to Rome at the invitation of Italian President Giorgio Napolitano.
Buckingham Palace has refused to discuss the details of the queen's condition, but experts say the most likely cause of her illness was the highly infectious norovirus, or winter vomiting bug.
Symptoms include diarrhea, vomiting, stomach pain and fever and it can also cause dehydration.