I'm with Darren, coca used in its herbal form is great stuff. Similar to caffeine with less crash, different (more pleasant/less stressful, imo) psychological side effects, and the big one for this thread... knocks any altitude-related symptoms right out of you.
Of course, the fact that some western scientists figured out how to turn it into a harmful, addictive drug through chemical refinement means that clearly a total ban on coca products and large-scale eradication of coca plants via herbicide is the only thing we can do, right (squeezing the supply, driving up the value, where does the money end up)? Obviously, once the coca plants are gone there will be no more cocaine, and then all the drug-addicts will stop getting high and turn into upstanding members of society. Right? I mean, the wholesale destruction of a cornerstone of Andean culture (no more sinister than coffee in its traditional use) and serious chemical damage to the environment is a small price to pay to achieve such a noble goal!
Thus, I will NOT complain that it's ridiculous that I can't drink Coca Mate instead of coffee in the mornings. That would clearly be selfish of me.
Really, though I was surprised to note that after discovering coca mate (made the mistake of drinking anise tea the first day I was in the andes, which provides no benefit) I was able to spring up the steep streets of La Paz (at 11000 feet or so in elevation) like I was back home at sea level. Later, climbing a mountain across from Machu Picchu (about 8000 feet) I felt a little sluggish so I munched some puffed coca beans and found that the problem was solved. Think chocolate-covered coffee beans, but with extra benefits for altitude.
Not saying this other stuff isn't great. Just saying it's unfortunate that due to the ridiculous politics surrounding coca in western cultures, we're missing out on a great altitude-adaptation aid.