Bush, 88, was admitted to Houston Methodist Hospital on Monday, though it wasn't announced until former President George H.W. Bush's office released a statement Tuesday night.
"She is in great spirits, has already received visits from her husband and family, and is receiving fantastic care," the statement read, promising to provide updates as warranted.
Jim McGrath, a spokesman for the former president, said there was "nothing new to report" on Wednesday.
"The message Bush has told friends and family is not to make a fuss over her. She and Mr. Bush spent New Year's Eve watching the Aggies bowl game on TV," said McGrath.
Bush and her husband, the 41st president, live in Houston and still make public appearances. Last week, they honored a Houston businessman and philanthropist with a Points of Light Award, a volunteer service award started by the former president.
The former first lady had a reputation for bluntness when her husband was president. Her son, George W. Bush, was the 43rd president.
The Bush family matriarch had heart surgery in March 2009 for a severe narrowing of the main heart valve. She also was hospitalized in November 2008, when she underwent surgery for a perforated ulcer. In 2010, she was admitted to the hospital after having a mild relapse of Graves disease, a thyroid condition for which she was treated in 1989.
Health concerns had been more common of late with her 89-year-old husband, the nation's oldest living former president. George H.W. Bush was released in January 2013 after he spent nearly two months at Houston Methodist Hospital, being treated for a bronchitis-related cough and other health issues.
There's no word when Mrs. Bush will be going home, but she is said to be doing well.
On Wednesday, the White House released the following statement
- "Michelle and I send our best wishes to Mrs. Bush for a speedy recovery. Barbara is blessed to have both a loving, supportive family by her side and a vibrant spirit that we hope will have her feeling better soon. I know I speak for Americans everywhere when I say that our thoughts and prayers are with Barbara and her family on this New Year's Day."
The Associated Press contributed to this article
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