Spokesman Jim McGrath said in statement that Bush was taken by ambulance to Houston Methodist Hospital on Tuesday evening as a precaution.
McGrath says the 90-year-old Bush "will be held for observation, again as a precaution."
Bush spent nearly two months in the same hospital and was discharged in January 2013 after treatment for a bronchitis-related cough and other health issues.
Bush, who can no longer use his legs, most recently appeared seated in a wheelchair at an event in November at Texas A&M University with his son, former President George W. Bush.
In June, the elder Bush celebrated his 90th birthday by making a tandem parachute jump near his summer home in Maine.