Queen Elizabeth II has left a central London hospital after a one-day stay caused by a severe stomach bug. She walked out of King Edward VII Hospital unassisted this afternoon wearing a red dress, and was driven away in a motorcade. The hospital stay had initially been planned for two days. She has been suffering from gastroenteritis, a stomach and intestinal inflammation. The 86-year-old queen has cancelled her engagements for this week due to the illness. It was her first hospitalization in 10 years. (More Queen Elizabeth II stories.)