The success of a natural cold remedy has spawned a number of knock-offs based on ginseng, but in most cases, the science behind the products is lacking.

Cold-fX was developed at the University of Alberta and has quickly become the biggest selling cold medicine in Canada.

A ginseng extract may help relieve cold symptoms.
(CBC)

"I think it's a big market," said Pam Lavold, a pharmacist in Edmonton. "I think everybody is jumping on the bandwagon and putting out their own product."

Labels of other ginseng-based products, some also containing other herbs, claim to help beat the common cold.

Although more research is needed, Cold-fX has shown some benefit. But the claims of other products are not supported by scientific evidence, said Heather Boon, an alternative medicine expert at the University of Toronto who has assessed the herbal remedies.

"There is no science that the specific combination of herbs in those products are going to be able to treat colds and flus," said Boon, a pharmacy professor.

Right now, no one is enforcing the label claims on the products, Boon said.

Health Canada is reviewing all claims by cold remedies to determine what, if any, should be allowed.

Puffy, blurry eyes, a runny nose and a pounding head led Marnie Weckel of Edmonton to scan the shelves of her local pharmacy in search of the popular cold remedy.

"I like that there has been clinical studies with Cold-fX," said Weckel. "I definitely purchase it because there is some kind of study."

One drawback of Cold-fX is cost. If people take two pills per day as study participants did, they would spend about $30 a month, or $120 in a cold season.

While Health Canada assesses thousands of herbal remedy claims, Boon suggests consumers need to be skeptical of label information and ads until the regulator finishes its work.