Colorado Springs: Sally Pearson's long-time rival, American Dawn Harper-Nelson, has been suspended for three months after testing positive for a banned substance.
The US Anti-Doping Agency announced the sanction on Wednesday (AEDT).
Dawn Harper-Nelson (right) competing against Australia's Sally Pearson.Credit: Getty Images
Harper-Nelson won gold in the 100 metres hurdles at the 2008 Beijing Olympic Games – when Australian star Pearson took silver – and claimed silver when Pearson triumphed four years later in London.
USADA said Harper-Nelson, 32, tested positive for the prohibited substance hydrochlorothiazide and related metabolites in an out-of-competition sample.
She told USADA it was caused by blood pressure medication prescribed by a physician to treat hypertension.
In a statement posted on her Twitter account, Harper-Nelson said she has learnt "a valuable lesson and hope my mistake will serve as a reminder to all athletes to be diligent in thoroughly checking any and all prescribed medications".
Her period of ineligibility started on December 1.
AP