From the
ESPN.com article:
"Sharapova, 28, said she had been taking the drug mildronate, also known as meldonium, for 10 years to address a number of health issues, including low magnesium levels. Meldonium is a blood flow-promoting drug banned because it aids oxygen uptake and endurance.
Sharapova said she had been getting the flu every couple months, had irregular EKGs and had evidence of diabetes, which runs in her family. She said she did not realize that mildronate and meldonium are the same drug and she was not aware when rules changed Jan. 1 to make the drug illegal. She said that when WADA sent an email about changes to the banned list in December, she did not click on the link to see that the substance had been added to the list."