Kenyan Daniel Wanjiru, winner of the 2017 London Marathon, has been provisionally suspended by the Athletics Integrity Unit.
On Tuesday, the AIU website confirmed that a charge has been issued for \"use of a prohibited substance/method\".
The 27-year-old cannot participate in any competition until a hearing has taken place.
Wanjiru also won the 2016 Amsterdam Marathon and has finished eighth and 11th in the past two years in London.
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