Olympic 3,000m steeplechase champion Ruth Jebet has been given a four-year ban after testing positive for man-made EPO.
The 23-year-old Bahrain athlete was suspended in February 2018 after failing an out-of-competition test.
Jebet told the Athletics Integrity Unit in March 2018 she had not taken it intentionally, but a disciplinary tribunal has now ruled against her.
The AIU said the ban would run from the date of the initial suspension in 2018.
Jebet, the former 3,000m steeplechase world record holder whose landmark was eclipsed by Kenya's Beatrice Chepkoech two years ago, tested positive for the banned blood booster r-EPO (recombinant erythropoietin) on 1 December 2017.
Recombinant erythropoietin is a man-made version of natural erythropoietin, and improves athletic performance by stimulating the production of more red blood cells.
The AIU ordered the disqualification of all her results between 1 December 1 2017 and 4 February 2018.
Kenya-born Jebet has the right to appeal against the suspension, but currently will not be able to defend her Olympic title in Tokyo this summer.