New Zealand Olympic athlete Liza Hunter-Galvan has been banned from marathon running for two years after testing positive for a banned hormone.
The United States-based runner tested positive for erythropoietin (EPO) in an out-of-competition test done at her home in San Antonio, Texas, in March this year.
Two months later, the Olympic laboratory in Los Angeles confirmed the presence of the performance-enhancing drug, which boosts the blood.
Hunter-Galvan then requested her B sample be tested, and that also came back positive for EPO.
At a Sports Tribunal hearing on Thursday, she admitted taking the drug.
She has been banned from competing for two years from 29 May, when she was provisionally suspended following the first test.
In her statement to the tribunal, Hunter-Galvan admitted taking the drug three times, but said she stopped using it because of side-effects such as stomach pain, chest pain and headaches.
Hunter-Galvan finished 35th in the marathon at last year's Beijing Olympics. She also competed at the Athens Games in 2004.
Drug Free Sport chief executive Graeme Steel says this is one of the most serious cases the organisation has come across.
Sad day for sport - Athletics New Zealand
Athletics New Zealand says it is a sad day for the sport and a blight on athletics.
"Liza's certainly let not only herself down very badly, but other athletes and the sport as a whole," says chief executive Scott Newman.
"We're lucky it's a very rare occurrence. But we're not naive enough to think that our athletes aren't exposed or tempted by the use of performance-enhancing substances.
"In this case, it's just extremely disappointing that Liza made a very, very bad choice."
Athletics New Zealand had planned to name Hunter-Galvan in the 2009 World Championship team for Berlin but she withdrew from selection.