In a small storefront on a bleak, wind-swept Andean plateau, Timotea Cordova offers an oxygen-deprived visitor a traditional elixir to ward off the breathless effect of the high altitude.

Dropping a few shriveled tuber roots into a blender, the 80-year-old Quechua Indian shopkeeper promises with a playful glance that the concoction will also provide a leg up later in the bedroom.