Nigeria's Blessing Okagbare has tested positive to banned substance and has provisionally been suspended from the ongoing Tokyo Olympic.
She was due to compete in the semifinals of the women's 100m this morning before the Athletics Integrity Unit (AIU) announced her suspension.
The AIU said in a statement issued this morning that the 32-year-old had tested positive for a human growth hormone following an out-of-competition test on July 19.
It stressed that Okagbare was notified of her provisional suspension this morning.
The body declined making any further comment at this stage.
Okagbare, Olympic long jump silver medallist in Beijing in 2008, had posted a time of 11.05 seconds in winning her 100m heat and was set to line up against Asher-Smith and Jamaica's Elaine Thompson-Herath in the first semi-final.
The news comes two days after 10 other Nigerian athletes were declared ineligible for the Games.
The AIU ruled they were unable to take part because of non-compliance with out-of-competition drug testing requirements in the run-up to the Olympics.
The 10 were part of the 20 barred from the Games from seven countries that included; Belarus (3), Ethiopia (1), Kenya (2), Morocco (1), Ukraine (3), and Bahrain (0) whose athletes missed three Out of Competition Tests (OCT).