In a study detailed in the Annals of Family Medicine, groups given the herbal cold remedy Echinacea recovered at the same rate as groups who were given either Echinacea or a placebo, without being told which one, or who were given nothing at all. But those who had proclaimed their faith in Echinacea's effectiveness before the study began reported feeling better sooner.
That's actually a huge difference, said lead researcher Dr. Bruce Barrett, of the University of Wisconsin, Madison. No treatment out there has ever been shown to reduce the duration of colds.
The study affirms that overcoming an illness, particularly a naturally fleeting one like a simple cold, entails a mental aspect. If a person believes their remedy is working, in all likelihood it will.