We have previously gone into the many ways a study of a natural substance can lead to a negative result, some an inevitable consequence of studies intended for synthetic substances, some which almost feel engineered to fail - here is a new one.

I am sure all of us who use herbal medicine remember the negative study of Echinacea and its use against the common cold?  Now comes another study which shows it to be very effective.

Research from  the University of Connecticut School of Pharmacy published in the Lancet shows "Using a method that calculates the Odds Ratio of incidence of the common cold in the pooled participants, the researchers found that echinacea decreased the odds by 58 per cent (the statistically significant odds ratio was 0.42 with a 95 per cent confidence interval ranging from 0.25 to 0.71).

They also found by using a random effects statistical model that the effect of echinacea was to reduce the duration of a cold by 1.4 days (the statistically significant weighted mean difference was -1.44 with a 95 per cent confidence interval ranging from -2.24 to -0.64)."  

The reason for the different results? The first study looked only at Echinacea's effect on Rhinovirus - which is only one of app. 199 viruses involved in the common cold.  Echinacea may not help with Rhinovirus, but is apparently extremely effective against the rest!