TORONTO -- IOC president Jacques Rogge said Tuesday that he had a "gut feeling" the use of the designer steroid THG was not widespread.

"I have this gut feeling, but it's only a gut feeling, that it's only a very localized issue," Rogge said in a telephone interview with The Canadian Press from IOC headquarters in Lausanne, Switzerland. "It is not probably a worldwide issue."

Rogge spoke after announcing the cancellation of his trip to Canada this week because of the flu. He was scheduled to attend a seminar in Vancouver, British Columbia, on preparing to host the 2010 Olympics.

Tetrahydrogestrinone, or THG, is an anabolic steroid that was undetectable by doping experts until this past summer.

Four U.S. athletes tested positive for it at the national championships. Dwain Chambers, the European 100-meter champion, also tested positive in an out-of-competition check in Germany in August.

Tim Montgomery, the world record-holder in the 100 meters, has appeared before a U.S. grand jury investigating a laboratory that supplies nutritional supplements.

Dozens of other athletes, including baseball star Barry Bonds, boxer Shane Mosley and several NFL players, also have been subpoenaed. All have been customers of the Bay Area Laboratory Co-Operative, or BALCO.

Rogge called THG a "designer drug," meaning it was manufactured by a local laboratory.

"There's only one lab that will ever produce a designer drug," he told Canadian Press. "It's probable around this lab there was a number of athletes who abused the drug.

"I don't expect it to be widespread on a worldwide basis. I may be proven wrong. We may see it was mostly a problem of a local community using that drug."

The IOC has said it wants to test samples from the 2002 Salt Lake City Olympics for THG. Samples from this year's track and field world championships are being retested.