As of the new year, world anti-doping regulations added marijuana to the list of banned substances. It will start testing for it at competitions where anti-doping testing is already done.

Canadian Olympic diver Philippe Comtois says he supports a ban on marijuana -- and any other kind of drug. Comtois says he's seen other athletes use pot and doesn't like the effects.

"I've seen divers smoke pot a day before, two days before, and they were really hot on that day. Maybe it was the pot, maybe not, you never know," Comtois says.

It's not clear if marijuana enhances athletic performance. Some say it can calm an athlete down. Others say it actually impairs co-ordination.

Regardless, it's now banned in all amateur competition, at home and abroad. Any athlete testing positive for THC, the drug found in cannabis, will be disqualified and could face suspension.

"If you accept the premise that doping can involve health risks, doping can involve actions contrary to the spirit of sport, quite apart from the performance enhancement, then treating cannabinoids in this way is quite justified," insists Joseph de Pencier, of the Canadian Centre for Ethics in Sport.

It's all part of the reaction to Canada's most infamous pot-positive athlete -- Ross Rebagliati. He created a huge buzz in 1998 when he was stripped of Olympic Gold in Nagano, Japan, after testing positive for THC. He claimed he'd only inhaled second-hand pot smoke. He eventually got his medal back.

But for some aspiring athletes, adding pot to the list of banned substances now makes no sense, since it's just when Ottawa is considering decriminalizing it.

"They're turning around and testing everyone for it. I think they're sending different messages, mixed messages to us," says graham Schmidt of the Alberta FreeSki Team

Still, the message for serious athletes is clear -- don't touch the stuff, even between competitions, since THC can stay in the blood for weeks.

"If you want to go for gold you don't take any chances," says Robert Crete of the Canadian Amateur Boxing Association.