Bush, 88, has been in and out of the hospital recently for complications resulting from bronchitis, Methodist Hospital said in a brief statement.
The hospital and Bush's spokesman in Houston, Jim McGrath, described Bush as in stable condition and said they expected the former president to be released by the weekend. He's been under hospital care for nearly a week.
"If you asked him today, he would tell you he feels good enough to get out this afternoon," McGrath said. "But the doctors have a different view. He's 88, and they're being extra careful, and understandably so." The illness was described as not life-threatening.
"Any time someone the president's age had bronchitis, there's concern about possible pneumonia," Dr. Amy Myunderse, who is in charge of Bush's care, said. "Mr. Bush's condition never progressed to that level."
Bush was treated with antibiotics and steroids, she said.
Bush was seen a few weeks ago attending a Houston Texans NFL game, something he does frequently. He has a form of Parkinson's disease that forces him to use a wheelchair or motorized scooter to get around. -- AP