Former U.S. first lady Barbara Bush was discharged from a Houston hospital on Saturday, a family spokesman said.

Mrs. Bush, 88, was admitted to Houston Methodist Hospital Monday for treatment of what an official statement said was "a respiratory-related issue." Bush family spokesman Jim McGrath later confirmed that the issue was pneumonia, but noted that it was caught early and well controlled.

McGrath told the media on Friday that Mrs. Bush was coming off a couple "truly great days" in which doctors were pleased at how well she responded to treatment.

"I cannot thank the doctors and nurses at Houston Methodist enough for making sure I got the best treatment and got back to George and our dogs as quickly as possible," the former first lady said in a statement released on Saturday.

Mrs. Bush is the wife of George H.W. Bush, the 41st U.S. president, and mother of George W. Bush, the 43rd president. She is one of only two women to be both the wife and mother of U.S. presidents. The other is Abigail Adams, wife of John Adams, the second U.S. president, and mother of John Quincy Adams, the sixth president.

Mrs. Bush has supported to advance the cause of universal literacy and founded the Barbara Bush Foundation for Family Literacy while as the First Lady. Since leaving the White House, she has continued to advance the cause. The Bush couple now live in Houston.