American pole vaulter Cole Walsh, who was suspended for three months after failing a doping test, said the cause was not cannabis but chocolate.
Walsh, 10th at the last World Athletics Championships in Qatar in 2019 tested positive for carboxy-THC, the main active ingredient in cannabis.
"I ate a chocolate bar containing THC to help me sleep during a flight, I didn't imagine it would represent enough carboxy-THC in my body to make me positive on a test," Walsh posted on social media.
In announcing the ban on Monday, the US Anti-Doping Agency (USADA) also said the 24-year-old had completed it.
Walsh tested positive after finishing third in an indoor meeting in Cottbus, Germany on 29 January, which therefore marked the starting date of his ban.
"Because Walsh has successfully completed an educational program about his marijuana use, his suspension period has been reduced by three months," USADA, which initially suspended the athlete for six months, said in its statement.