Archbishop Emeritus Desmond Tutu was admitted to hospital on Wednesday with a "persistent infection", the Desmond and Leah Tutu Legacy Foundation said.
"Archbishop Emeritus Desmond Tutu has checked into a Cape Town hospital for the treatment of a persistent infection and to undergo tests to discover the underlying cause," the foundation said in a statement.
He spent the morning in his office before checking into hospital.
"He was in good spirits and full of praise for the care he receives...
"Non-surgical treatment is expected to take five days," said the foundation.