how do allopathic and complementary & alternative medicine (CAM) differ?

Allopathic medicine is defined as a system of medicine that aims to combat disease by using remedies which produce effects that are different from or incompatible with those of the disease being treated. The medical community practicing this form of medicine includes medical doctors and others types of health professionals, e.g. nurses, pharmacists, and therapists. Common treatments within the scope of allopathic medicine include the use of drugs, surgery, or radiation and tend to focus on specific areas of the body, rather than an assessment of an overall condition. Allopathic medicine is also referred to as biomedicine, orthodox medicine, Western medicine, or conventional medicine.

Complementary and alternative medicines are, respectively, forms of treatment that are in addition to or a substitute for standard treatments. CAM medicines are typically outside the realm of allopathic medicine and therefore not subject to the testing procedures prescribed by the American Medical Association that are intended to prove the efficacy and safety of allopathic medicines and procedures. However,  many of these practices have been employed with success by other cultures throughout the world. There are five subcategories of CAM:

1. Alternative Medicine Systems: embody complete theories of health and practice
2. Mind-Body Therapies: use the power of the mind to influence bodily and somatic processes
3. Biologically-Based Therapies: involve the use of substances found in nature for health purposes
4. Manipulative and Body-Based: emphasize the physical manipulation or movement of the body to promote healing
5. Energy Therapy: emphasize the use of energy fields to maintain or restore health.

The aforementioned modalities include, but are not limited to, chiropractics, naturopathy, homeopathy, crystal therapy, megadose vitamins, dietary supplements, meditation, aromatherapy, massage therapy, folk healing, acupuncture, dietary supplements/nutraceuticals, tinctures, biofeedback, Ayurveda, Shiatsu, probiotics and spirituality/prayer.

Accordingly, the most relevant difference between allopathic medicine and CAM can be understood as differing views about how the body works. Ergo each employs a different approach to treatment. Such differences often result in incompatibilities between the different practices – something that can cause frustrations for patients seeking holistic treatment. Likewise, CAM is often disregarded by the allopathic medical community making collaboration between different practitioners difficult.

sources:

https://www.cancer.gov/about-cancer/treatment/cam
http://www.hopkinsmedicine.org/healthlibrary/conditions/complementary_and_alternative_medicine/types_of_complementary_and_alternative_medicine_85,P00189/
http://www.medicinenet.com/script/main/art.asp?articlekey=33612
Grzywacz, Joseph G., et al. (2007) Age, Ethnicity, and Use of Complementary and Alternative Medicine in Health Self-management’ Journal of Health and Social Behavior. 48(1):84–98.