Former US President George H W Bush is being treated for bronchitis in hospital in Houston, Texas, hospital and family officials have said.
Mr Bush, 88, has been in hospital for six days with a "lingering cough", his spokesman Jim McGrath told CNN.
His condition is not considered life-threatening and the former president is expected to be discharged this weekend, reports say.
Mr Bush is the oldest living former president and a World War II veteran.
He was Ronald Reagan's vice-president for two terms and president for one, serving in the White House from 1989 until 1993.
His chief of staff, Jean Becker, said Mr Bush was admitted to Houston's Methodist Hospital on Friday, after several visits in recent weeks, the Houston Chronicle newspaper reported.
His son, former President George W Bush visited on Sunday with his wife, Laura.
Ms Becker added that there had been concerns Mr Bush's condition might have developed into pneumonia and news of his treatment had not been made public "out of respect" for the former president.