Ethiopian marathon runner Etaferahu Temesgen Wodaj received a provisional suspension from the Athletics Integrity Unit (AIU) after allegedly testing positive for performance-enhancing drugs.
According to the AIU, Wodaj tested positive for the blood-boosting drug erythropoietin (EPO) and testosterone.
The 30-year-old claimed third place at May's Ottawa Marathon in a time of 2 hours 28min 44sec, before finishing eighth at last month's Toronto Waterfront Marathon in 2:27:21.
In 2018, she triumphed at the Ciudad de México Marathon in a time of 2:40:10.
Wodaj is now temporarily suspended from participating in any competition or activity prior to a final decision at a hearing conducted under the International Association of Athletics Federations (IAAF) anti-doping rules or the integrity code of conduct.
The news comes a month after Ethiopia's African Games 10,000 metres champion Berehanu Tsegu was provisionally suspended by the AIU after also testing positive for EPO.
Last year, Ethiopia was named top of a list of nations categorised by the IAAF most of risk at doping.
Along with Belarus, Ukraine and Kenya, they were among four countries included in Category A - Member Federations the IAAF believe are most likely to have doping problems.
Doping products are reportedly easily available in Addis Ababa, the IAAF warned.
Following their inclusion on the list, the Ethiopian Athletics Federation launched a major education programme among young athletes to warn them of the dangers of doping.