One of the unexpected aspects of staying in a hotel high in the Andes was the ready availability of a local treatment for altitude sickness (and headaches, and fatigue).
Coca leaves are not generally available in Chile - you have to go to really high altitudes, in areas where they're also considered a sacrament. But just as at sea level, it's the alcohol that gets locked up. The President of Bolivia attempts to explain why western drug policy toward the coca leaf is absurd; but although he's right, I doubt his opinion will have much impact.
(If you want a first-hand description of coca chewing, sorry, I guess I'm too much a product of our 'war on drugs' culture.)