Buckingham Palace officials released a statement on Sunday that the queen had symptoms of gastroenteritis. Officials said all of her official engagements for this week will be canceled or postponed as a precaution.
A spokesman for the Queen told the Associated Press that she was in "good spirits" and was otherwise in "good health" besides the gastroenteritis symptoms.
"She was not taken into hospital immediately after feeling the symptoms," the spokesman said. "This is simply to enable doctors to better assess her."
According to ABC News, the 86-year-old British monarch was last hospitalized 10 years ago. She is expected to be in the hospital for about two days.
ABC News contributed to this report.