Former British hurdler Colin Jackson feels inadequate drug-testing procedures are threatening to make a mockery of athletics.
His comments come after American sprinter Kelli White - who won the 100m and 200m at the World
Championships in Paris this week - tested positive for the stimulant Modafinil, which although not banned, is related to substances that are.
Jackson believes there needs to be a clear worldwide directive and the elimination of the grey area
over which drugs are legal or not.
Jackson told BBC Radio Five Live: "What we're seeing now is a whole mess - it is not structured and that is where the problem lies.
"What brings the whole credibility of the sport down is that there are no real answers to anything."
And Jackson singled out the American governing body USA Track and Field for particular criticism.
"The problem with USATF is that apparently they don't have the same degree of dope testing as we do in the UK," he said.
"Random dope testing is not taken on board as much as we do and I guess that's why a lot of these things happen."