They found it decreased the odds of developing a cold by 58% and the duration of colds by a day-and-a-half.

The results in The Lancet Infectious Diseases conflict with other studies that show no beneficial effect.

Experts believe Echinacea, a collection of nine related plant species indigenous to North America, may work by boosting the body’s immune system.

‘Marked effects’

Researchers, led by Dr Craig Coleman from the University of Connecticut School of Pharmacy, combined the results of 14 different studies on Echinacea’s anti-cold properties.

In one of the 14 studies the researchers reviewed, Echinacea was taken alongside vitamin C. This combination reduced cold incidence by 86%.

When Echinacea was used alone it reduced cold incidence by 65%.

Even when patients were directly inoculated with a rhinovirus – the most common cold-causing virus – Echinacea reduced cold incidence by 35%.

The researchers’ report said: “With over 200 viruses capable of causing the common cold, Echinacea could have modest effect against rhinovirus but marked effects against other viruses.”

Read more as it was originally published on BBC.