Ohuruogu, 24, hit the headlines for the wrong reasons in 2006, when she received a year's ban for missing three out-of-competition drugs tests.
However, within 24 days of the end of her suspension she returned to win the gold medal at the 2007 World Championships.
She was then successful in having a lifetime ban on Olympic participation overturned and takes part in her second Games after reaching the semi-finals in Athens.
In Beijing, the semi-finals of the women's 400m take place on 18 August, with Ohuruogu expected to go for gold in the final the following day at 1410 BST.
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