Former first lady Barbara Bush was hospitalized Saturday in Houston to undergo routine tests but doctors don't suspect anything serious, a family spokeswoman said.
Bush, 84, was being treated at Methodist Hospital and should be released in a day or two, spokeswoman Jean Becker said late Saturday.
"She hasn't been feeling well for about a week, and the doctors thought she should come in and undergo a battery of tests," Becker said. "It's not serious. She just hasn't been feeling herself and they're just trying to figure out why."
Becker declined to provide details, but said former President George H.W. Bush drove his wife to the hospital Saturday morning after consulting with her doctors. A hospital spokeswoman declined comment, saying information was only being released through the family.
NBC News reported that the former president was with her at the hospital.
Sources told NBC that the problem was not believed to be related to her heart or the aortic valve operation that she underwent in March 2009.
Mrs. Bush underwent surgery then to have her aortic valve replaced by a valve from a pig. That surgery was performed because she was suffering from a severe narrowing of the main valve.
Mrs. Bush underwent surgery in November 2008 for a perforated ulcer. When she lived at the White House, she disclosed she was suffering from an overactive thyroid ailment known as Graves' disease. The disease causes teary eyes and double vision, according to her doctors.