There have been some doubts in the medical and scientific research community that Cold-fX is not as effective as has been claimed. Skeptics allege that the science does not fully support the claims being made. Other scientific research has however produced significant results (Predy 2005, McElhaney 2006).

Other criticisms of the studies point out that they have so far been very small scale, and that test subjects have not actually been deliberately exposed to any particular strain of cold virus. This would make it difficult to assess whether any preventative benefits truly exist.[8] Skeptics have pointed out that there aren't enough studies on the effects of any form of Ginseng on the common cold to form any conclusions.[9]

Skeptics[who?] argue that Cold-fX has not been tested for its ability to treat a cold after an individual has been infected.[10] In addition, no studies have yet been performed to assess the possible long term side effects of taking the pills every day during the cold and flu season.[8] Afexa Life Sciences Inc. (formerly called CV Technologies Inc.), the makers of Cold-fX, were criticized[weasel words] for making health claims about this product that have never been tested or verified scientifically. Up until February 2007, the company advised a regimen of 18 pills over a course of 3 days in order to obtain "immediate relief" from a cold. Health Canada's review of the scientific literature confirmed that this is not a claim that CV Technologies Inc. is entitled to make.[11] The company formulated a separate product for this usage. A CV Technologies press release explained the change in the dosing regimen as a choice to take a two-tier approach application to Health Canada.[12]

http://en.wikipedia.org/wiki/Cold-fX