Rhubarb extract for your libido? A GP on alternative medicine

This is a rant about complementary medicine but many of the sentiments expressed can, and do, apply to many legitimate therapies.
History:
Many years ago, I had to suppress my mirth when a relative asked me whether he should take his tonic, Mist. Gent. Alk., before or after meals.
My mate, the local chemist, suggested I prescribe Mist. ABT (Any Bloody Thing) and he would dispense something harmless from his shelves.