The 86-year-old monarch was smiling as she walked out of a London hospital Monday morning.
A spokesperson said the queen was hospitalized as a precautionary measure. She was admitted Sunday after experiencing symptoms of gastroenteritis.
She has canceled or postponed the rest of this week's planned events and appearances, including a trip to Rome.
The queen is generally believed to be in good health. This was her first hospitalization in 10 years.
