Taking Echinacea may reduce the risk of catching a cold by up to 58 percent, according to a review of several studies published online and in the July edition of The Lancet Infectious Diseases.

The review, authored by Dr. Craig Coleman of the University of Connecticut School of Pharmacy at Hartford Hospital in Hartford, Conn., also found that the herbal supplement may reduce the duration of colds.

The authors found that if Echinacea was used in attempt to prevent a cold, it reduced cold incidence by 65 percent. If it was used to reduce colds in patients inoculated with the cold-causing rhinovirus, it reduced the incidence by 35 percent.

Just one of the 14 studies reviewed combined Echinacea with vitamin C and it showed that, used together, the two could reduce the incidence of catching a cold by 86 percent.

Echinacea is a collection of nine related plant species indigenous to North America. Echinacea angustifolia, Echinacea pallida, and Echinacea purpurea are the most common species recognized for their medicinal value.

Although Echinacea was shown to reduce the incidence of cold for those taking it, the authors said more research is needed to determine why the herb has a cold-suppressing effect.