All remedies need to be subjected to double-blind placebo controlled trials on a sufficient number of subjects to allow objective statistical analysis. Failure to prove traditional remedies in this way may leave them in the same category as many quack remedies that have clinical success. Studies have shown that numerous remedies that were popular for centuries are ineffective or harmful, e.g. bleeding, purging, the use of cathartics and counter-irritation - or the use of disgusting remedies (excreta, spiders webs, dogs lungs, etc). Studies help bring useful old remedies into general use (as happened with reserpine and Dhatura), and ensure that useless remedies are recognized as such.