The former left-back, 52, updated fans on his condition via his Instagram page, which included a picture of him smiling in a hospital bed.
He also denied rumours that he had suffered a heart attack.
"I would like to clarify recent information that has been circling," he wrote.
"I recently underwent a preventative medical procedure, planned in advance with my medical team. The procedure was successful, and I am well. I did not suffer a heart attack. I am recovering well, and looking forward to returning to full fitness and resuming my professional and personal commitments soon. I sincerely thank everyone for the messages of support, care, and concern. I would like to reassure everyone that there is no cause for concern. My heartfelt thanks go to the entire medical team who took care of me."
Carlos won four La Liga titles and three Champions Leagues across 527 appearances for Real Madrid, and lifted the World Cup with Brazil in 2002.
Renowned as a free-kick specialist, his other clubs included Palmeiras, Inter Milan, Fenerbahce and Corinthians.
