The five-time Grand Slam champion said she was notified by the International Tennis Federation several days ago that she tested positive for meldonium.
In Angelique Kerber's first Grand Slam final on Saturday, she defeated Serena Williams 6-4, 3-6, 6-4. In the men's tournament on Sunday, Novak Djokovic beat Andy Murray 6-1, 7-5, 7-6.
Williams defeated her big sister 6-2, 1-6, 6-3. It keeps alive her quest to win each of the year's major tournaments, the first time the feat would be accomplished since Steffi Graf did it in 1988.
Tennis players Serena Williams and Novak Djokovic both have the potential to win Grand Slams, one of the rarest achievements in sports. But it's not an easy feat.