(Reuters) - Jamaican Olympic relay silver medalist Sherone Simpson said on Sunday she had tested positive for a stimulant at last month's national championships.
Simpson, 28, was a member of the Jamaican team that finished second in the 4x100 relay at last year's London Olympics.
She finished equal second in the 100 meters at the 2008 Beijing Games and won a gold medal in the 4x100 relay four years earlier in Athens.
"This is a very difficult time for me," Simpson said in a statement to Reuters.
"I was notified on July 14, 2013 that my urine sample taken at the National Senior Championship, June 21, 2013 after the 100m finals returned a positive analytical finding for a stimulant, oxilofrine (methylsynephrine).
"As an athlete, I know I am responsible for whatever that goes into my body. I would not intentionally take an illegal substance of any form into my system."
(Reporting by Gene Cherry in Raleigh, North Carolina; Editing by John Mehaffey)