The Department of Correctional Services “can confirm that former president Jacob Zuma has today, 6 August 2021, been admitted to an outside hospital for medical observation,” it said in a statement.
Zuma, 79, is scheduled to attend the resumption of a long-running corruption trial on Aug. 10.
The hearing will include a plea to drop 16 charges of fraud, graft and racketeering against him related to the 1999 purchase of fighter jets, patrol boats and equipment from five European arms firms when he was deputy president.
He is accused of taking bribes from one of the firms, French defense giant Thales, which has been charged with corruption and money laundering.
In a separate case, Zuma was handed a 15-month jail sentence in late June for snubbing a commission probing state corruption under his 2009-19 presidency.
Zuma began his sentence on July 8 at Estcourt prison.