This is the second hospitalisation in as many months for the frail anti-apartheid hero. On April 6 he was released after being treated for pneumonia during a 10-day stay.
The Nobel Peace Prize winner has stayed in hospital four times in just over half a year, mostly over problems connected with his chest.
In December 2012, he was hospitalised for 18 days for a lung infection and for gallstones surgery, his longest stay in hospital since he walked free from 27 years in jail in 1990.
In March he was admitted for a day for a scheduled check-up and during his 10-day stay weeks later, doctors drained a build-up of fluid, known as a pleural effusion or "water on the lungs", that had developed in his chest.
Mandela was diagnosed with early-stage tuberculosis in 1988 during his 27 year jail term and has long had problems with his lungs.
He has also had treatment for prostate cancer and has suffered stomach ailments.
His eyesight is also said to be highly sensitive to flashlight due to damage caused by the long time he spent working on a quarry during his imprisonment on Robben Island.
Mandela has not been seen in public since the World Cup final in 2010, where he appeared on the pitch before kick-off.