(CNN) -- Former first lady Barbara Bush was discharged from Houston Methodist Hospital on Saturday, a family spokesman said.
"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," Bush said.
She was released after six days of treatment for pneumonia, a family statement said.
Bush, 88, is the wife of the 41st U.S. president, George H.W. Bush, and the mother of the 43rd, George W. Bush. President Barack Obama and former President Bill Clinton sent their best wishes to Mrs. Bush for a full recovery.
In her role as first lady, she championed the cause of literacy. She formed the Barbara Bush Foundation for Family Literacy in 1989. That was the same year that she made public that she had been diagnosed in 1988 with Graves' disease, an autoimmune disease that commonly affects the thyroid.
In 2010, she was hospitalized for what doctors at the time described as a recurrence of Graves' disease. She underwent heart surgery in 2009 after doctors found hardening in one part of her aorta. In 2008, she was hospitalized after suffering abdominal pain. She underwent surgery for a perforated ulcer.