Shamanism is one of those really loosely defined terms that eludes and confuses all the same. It is a broad field of evolutionary, experimental medicine that is as unique and individual as the practicing shaman. So, when you ask a shaman: “What exactly is shamanism?” You are bound to receive a variety of answers. The consistency you will find in these answers, though, is an honest response about spiritual life.
Shamanism refers to a universal conceptual framework found among indigenous, uncivilized (i.e. politically unstratified), tribal humans. It includes the “belief” that nature (the world) has two aspects, the ordinary world, accessed through ordinary consciousness, and the spiritual world, accessed through an altered state of consciousness, or “trance,” induced by shamanic practices such as repetitive drumming, fasting, or herbal drugs. According to shamanic theory, the spiritual and ordinary worlds interact continuously, and a shamanic practitioner can gain knowledge about how to alter or to guide interaction with ordinary reality by taking direct action in the spiritual aspect of the world.
I recently read this article, posted in a shaman forum about Shamanic Medicine. It very succinctly summarized my experience practicing shamanic healing with clients: it is real in the sense that it is not mystical, woo-woo, or otherwise esoteric. It takes arduous training, practice, and education. But, then it is very easy to get repeatability and predictability like any other medical practice our culture is comfortable following already. In fact, the article details a clinical trial performed on shamanic medicine with an 83% success rate of healing.
I know that as more brave scientists are willing to explore shamanic medicine, the more we understand quantum mechanics, the more studies of the true power of the heart in creating reality and consciousness, the more shamanic medicine will be recognized as effective treatment of disease.