Mike Tyson's Wife -- HOSPITALIZED ... Severe Stomach Pains

Mike Tyson rushed his wife to the hospital yesterday in Chicago ... after she complained of excruciating stomach pains, TMZ has learned.

A rep for Tyson tells TMZ, the boxing legend and his wife Kiki are currently in Chicago for Mike's one-man show "Undisputed Truth" -- and yesterday, Kiki fell extremely ill ... to the point where she needed immediate medical attention.

According to the rep, Mike took her to the hospital where she was admitted to the ER and released shortly after.

So far, it's unclear what caused the stomach pains ... but we're told Kiki will be returning to the hospital soon for a follow-up.