Arsenal manager Arsene Wenger has raised concerns over the purity of football saying soccer authorities should introduce compulsory blood testing to check for drugs cheats.
His comments come after a week where the head of the Spanish soccer league was forced to deny allegations he was complicit in the provision of banned substances to players while president of Real Sociedad.
A damning report into doping in Australian sport was also released.
"I hope England is clean from doping but I don't know. When you take a UEFA doping control, they do not take blood. They take only urine. I have asked many times for that to be changed"
Arsenal boss Arsene Wenger
"I do not think, in football, we do enough," Wenger told British newspapers on Saturday.
"It is very difficult for me to believe that at a World Cup, where you have 740 players, you come out with zero problems. Yet mathematically that is what happens every time."
Soccer has long viewed itself as largely immune from the use of performance enhancing drugs which has badly tarnished other sports such as cycling.
However, Wenger thinks doping could be as bigger problem in soccer as match-fixing following European police revelations this week of hundreds of rigged games.
"I hope England is clean from doping but I don't know. When you take a UEFA doping control, they do not take blood. They take only urine. I have asked many times (to the European governing body) for that to be changed," he said.
"We could go a lot deeper into control. I would support blood testing and UEFA is ready to do it but it poses ethical problems because not everybody is ready to accept that they will check blood."
Blood can be tested for more banned substances than urine and can also be taken from a player quicker, decreasing the chances of any drugs avoiding detection.
Britain's Olympic and U.S. Open champion Andy Murray said earlier this month that tennis also had to increase the number of blood tests, which are now common in cycling.