The Homeoapthic treatment for the common cold provides a useful example.

One of the common Homeopathic remedies for a cold is Allium Cepa, made from the common onion. Because onions make your nose run and your eyes tear, the remedy Allium Cepa can aid the body in flushing out the cold virus by working with the already runny nose and tearing eyes, hereby speeding up recovery.

.... an intense amount of clinical and personal experience have verified the effectiveness.

Update 2015-01-15