There is really only one way the body can become well. This seems like an over simplification of something that is complicated but it is not.
Although there are many different techniques or therapies to assist this "one way," the body can only get well by regaining its equilibrium, otherwise known as homeostasis. So for example a chiropractor helps this by adjusting the spine and providing nutritional counseling. The medical doctor does this by sewing up a wound or giving medicine, and so on.
So what is it that really does the healing? For thousands of years in hundreds of different cultures it has been known that we have an innate force which is identifical to life itself. Any illness or injury causes this innate life force to react and cause so-called symptoms of disease to appear. As a person's life force reacts it will push out or expel whatever it is that caused the problem. This is always favorable because without such a reaction a disease can become lodged within the body and become chronic. A major problem today is that we often forget this and try and suppress a symptom instead of trying to find and correct the cause. The basis of natural healing - including chiropractic - is to eliminate the causes of health problems. This natural approach differs from trying to cover up or suppressing the body's ability to heal itself.
An interesting quote attributed to Thomas Edison: "The doctor of the future will give no medicine, but will interest his patients in care of the human frame, in diet, and in the cause and prevention of disease."