Many of my patients have come down with a nasty cold in the last two weeks – runny nose, cough, hoarseness, sore throat and the kind of fatigue that makes lifting your head off the pillow seem unnecessarily ambitious.  And just in time the Annals of Internal Medicine published a study to give them valuable advice.

The effects of echinacea on the common cold have been studied many times previously, though never as rigorously as in this study.  A definitive benefit has never been proven.

This study enrolled over 700 people who had just developed a cold.  They were randomized into four groups.  One group took no pill.  A second group took echinacea daily and was told that they were taking echinacea.  The last two groups took either a placebo pill or echinacea but were not told which they were taking.  They recorded the severity of their symptoms twice a day.

The results were positively meh.  The average duration of symptoms in the group knowingly taking echinacea was 6.8 days.  In those unknowingly taking echinacea it was 6.3 days.  Those taking placebo felt sick for an average of 6.9 days, and those taking nothing for 7.0 days.  Note that this shows a slight decrease in duration of symptoms between the two echinacea groups and the other two groups.  This difference was so small it was likely to have been due to chance (that is to say, the difference was not statistically significant).  But even if the difference is real it would amount to decreasing the misery of a cold that lasts a week by only several hours.

So this trial suggests that echinacea either doesn’t help in treating the common cold or it has a very small benefit.

Remember, nothing has been proven to decrease the duration of the common cold yet.  The best that you (and your doctor) can do is to make the symptoms less miserable until you recover.

I wish all of us a healthy, joyous and prosperous 2011.

Learn more:

Annals of Internal Medicine Summaries for Patients:  Echinacea for the Common Cold

LA Times Booster Shots:  Echinacea for a cold? Eh, don’t bother, study concludes

NPR Health News Blog:  If Echinacea Does Anything For Colds, It Isn’t Much

And lest echinacea have hurt feelings, Vitamin C doesn’t help in treating colds either.