In its natural, pure form, coca is an incredible medicinal plant, and was sacred to the Incas as the divine leaf of immortality. It is also sacred to the Kogi tribe. It contains around 1% cocaine I think, but it also rich in a host of antioxidants, and minerals such as potassium and magnesium, that tend to be lacking in other areas of the Indian's diet. And they are used as an entheogen, I think healers or shamans are able to commune with the energy essence in the leaves to some degree.
It is also good at treating altitude sickness. I recall, a few summers ago now, traveling from Cusco in the Andes, 3,800m above sea level, to Manu National Park with my best friend, with our crazy guide, in a car that had seen more years than I had! We had the good fortune of going to a Coca farm on route, and at one stage, we were almost 5,000m above sea level! I felt a bit light headed and weird, not unpleasant, but not normal either! Well a nice mug of coca tea really sorted myself and my friend out. We made it to Manu, and I had the most amazing ayauhasca experience of my life...special trip
I recall the shaman was chewing lots of coca leaves during that ceremony, and he had also partaken of the ayahuasca.
Coca in its raw, natural form is a purely beneficial food and medicine. It is only when we process it, is it tainted and becomes a corrosive and, for some, addictive poison.