She is now said to be on an IV drip in the hospital as doctors try to rehydrate her, but she could be released as early as Wednesday night.
Mariah's emergency admission came one day after she appeared at an event Tuesday night for Pier 1 Imports, the home-furnishings chain.
The 45-year-old mom of twins also appeared in the Macy’s Thanksgiving Day Parade in New York on November 26 and performed her classic "All I Want for Christmas Is You."
The Grammy award winner is set to perform this weekend at New York radio station Hot 97’s “Home for the Holidays” concert in New Jersey. Next week she will begin an eight night residency at Manhattan’s famed Beacon Theater.
INSIDE EDITION has not received a response to calls to Mariah's publicist.