The Vancouver Olympics have had no positive doping tests since the Games opened on February 12, with more than two thirds of the 2,100 tests already conducted.
The only case was a Russian athlete reprimanded for using a light stimulant on February 6 after testing positive. The Games end on February 28.
Surely, we are having cleaner and cleaner Games, IOC medical commission chief Arne Ljungqvist told Reuters in an interview.
The pattern seems to be fairly clear... people are being caught more before they become Olympians and we find less and less (doping) during the Games.
The International Olympic Committee (IOC) has urged doping agencies and sports federations to boost drug-testing in the months leading up to the Games with about 30 athletes in several countries nabbed before the Vancouver Olympics.
Ljungqvist said athletes' performances in events like last year's world athletics championships in Berlin was further evidence that major competitions were getting cleaner.
People won gold medals in Berlin with performances they would not have even qualified for the final of their competition in Olympics 20 years ago, he said.
Ljungqvist said the IOC was also up to date with new substances being produced by pharmaceutical companies that may not yet be on the market but were already in the hands of cheats.
Athletes' samples from Vancouver will be kept for eight years to allow re-testing for new performance-enhancing drugs.
There is a steady outflow of new substances on the market, said the 78-year-old Swede, who is also the World Anti-Doping Agency Vice President.
We are fairly well aware of what is in the pipeline and what may be available already, although some substances may not be officially marketed.
There are new generations of (performance-boosting) EPO or of substances for treating people who have anemia and difficulties with their blood quality. We are keeping (athletes') samples for that purpose.
We know that we will test for them later on. In case we do not have (the test) already, he said, smiling.
Five athletes were sanctioned, including men's 1,500m champion Rashid Ramzi who was stripped of his medal, months after the 2008 Beijing Olympics following positive tests for blood booster CERA EPO during re-testing for the specific substance.
We have no hurry, said Ljungqvist, who competed at the 1952 Helsinki Games as a high jumper. Cheats know that they may not be detected today but they may be tomorrow.