Maria Sharapova has been banned for two years by the International Tennis Federation for using a prohibited drug. The Russian tennis sensation was provisionally banned in March after testing positive for meldonium at Australian Open in January this year. The heart disease drug, which 29-year-old Sharapova says, she has been taking since 2006 for health issues, became a banned substance on 1 January 2016. The five-time Grand Slam winner said she cannot accept the unfairly harsh ban and will appeal against it.Sharapova will now challenge the suspension, at the Court of Arbitration for Sport. In a statement, she said the tribunal concluded her offence was "unintentional" and that she had not tried to use a "performance enhancing substance".The tribunal ruling said Sharapova also tested positive for meldonium in an out-of competition test, as well as in the aftermath of her Australian Open quarter-final defeat in January. Tribunal treated both results as a single anti-doping violation.