Ballesteros, the winner of three British Opens and two Masters, was taken to La Paz hospital after briefly losing consciousness, the hospital said in a statement. His condition was stable, and he was undergoing diagnostic tests, the hospital said.
No further information on his condition or treatment would be made available under instructions from Ballesteros' family, the hospital said.
The 51-year-old Ballesteros, who has a long history of back pain, officially retired from competition in 2007. He earned 50 victories on the European Tour.
He's known for his brilliant improvisational play and was a stalwart of European golf, playing a key role in reviving the continent's fortunes in the Ryder Cup both as a player and later as captain when he led Europe to victory over the United States in Spain in 1997.
He was elected to the World Golf Hall of Fame in 1999.