The president underwent the test on Tuesday on the advice of physicians and received his results on Wednesday night, the statement said, adding Ramaphosa had held meetings with a variety of people in recent weeks.
South Africa currently has 709 confirmed coronavirus cases, with no reported deaths. Health Minister Zweli Mkhize has warned infections are expected to keep rising.
Ramaphosa has been praised for ordering some of the toughest measures on the continent, including a 21-day lockdown that is due to start at midnight on Thursday.
He has also deployed the army to support the police.
Businesses are bracing for the lockdown, with Airlink becoming the latest local airline to suspend flights from midnight on Thursday. State power utility Eskom has applied for its critical staff to be exempt from the stay at home order so electricity supplies can continue uninterrupted. (Reporting by Emma Rumney; Writing by Tim Cocks Editing by Alison Williams and Frances Kerry)
The US government requires all homoeopathy "treatments" to specifically state that they do not work.