British sprinter Richard Kilty is doubtful there will be a "clean" Olympics in Rio this year, given the ongoing doping scandals in athletics.
Kenya have only just agreed a "roadmap" to potentially participate at the games after the World Anti-Doping Agency declared the nation "non-compliant".
The Russians are also currently banned from international competition following a Wada report.
"I'm not confident it's going to be clean," Kilty told BBC Look North.
"There will be athletes who are in finals and win medals, not in every event, as we're seeing failed tests all the time."
Teessider Kilty is desperate to add Olympic honours to his 60m world indoor and European titles, with June's Birmingham Grand Prix serving as trials for qualification.
His concerns about the forthcoming Rio competition come on the back of an announcement earlier this month that up to 31 athletes from six sports could be banned for 2016, after athletes' samples from 2008 are being retested.
"If you look at the World Championship 100m final in Beijing, there were four in that final who were pervious drugs offenders, who had taken a ban for using performance-enhancing drugs," Kilty added.
"It's something I will have to put to the back of my mind, hopefully people will go out there and win medals in Rio clean and shine some light onto the sport.
"As British athletes we get tested I think the most in the world, but unfortunately in other countries it's not the case that athletes are tested as strictly as we are.
"Hopefully the IAAF and Wada can make a big stand and try to put and end to it all, I don't know how but it would be great if we could have an entirely clean sport."