The 74-year-old boxing legend is in "fair condition" and is being treated by a team of doctors, according to the statement. He's expected to have a "brief" stay at the hospital.
Ali has been battling Parkinson's disease for 30 years, which affects the central nervous system, notably causing tremors. His friend Davis Miller told WHO in March that the sports icon is now largely confined to a wheelchair but "still fights every day all day long."
"That man continues to put me in awe. He's such a fighter, still, when at times he seems weak and not able to handle it," Ali's daughter Laila Ali recently told WHO. "He comes through stronger than ever. He's still fighting regardless and I love my dad for that."
Ali was last hospitalized in January 2015 for follow-up care for a severe urinary tract infection. He was released just a few days later.