Sometimes one measures mice by the amount of indignant squeaking one can hear.
Using the carefully tested (in the West) power of the most potent class of drug known to human kind (placebos - generally improve outcome vs no treatment on virtually all medical conditions), even the most incompetent witch doctor can have some people believing that the magical tea made from randomly selected herbs and spices has miraculous powers.
This is why double blind studies use placebos whenever possible. Otherwise, the new "miracle treatment" which "cures" a large percent of those complaining of an illness may later be proven to be no better than taking an empty capsule. Discovery and controlling for the placebo effect was an even bigger step forward than testing of a new treatment against no treatment at all.