These two terms are often used interchangeably, but they mean different things. According to the National Center for Complementary and Integrative Health (NCCIH), alternative medicine refers to medical therapies used in place of conventional medicine (allopathic). Complementary medicine refers to medical therapies used along with conventional medicine.

Complementary and alternative medicine practitioners see the body as responsible for its own healing. Complementary and alternative medicine practitioners try to find the best approaches to support the body in its self-healing. They also see themselves as teachers, instructing you on ways to heal. Docere is a central part of most alternative and complementary practitioners. This term refers to the healer as teacher.

Another complementary and alternative medicine principle is prevention, or doing all you can to keep yourself healthy and avoid illness. This is a principle used by conventional medicine, as well. Some complementary and alternative medicine practitioners believe in various types of balance between forces or energies that are outside of the body to which the body needs to align itself in order to heal. An example of this is acupuncture.

Homeopathy is based on the idea that "like cures like." The theory is that a homeopathic remedy stimulates the body with very tiny amounts of a substance. If this substance were given in large amounts, it would cause illness. Homeopathy triggers the natural healing process.

Naturopathy emphasizes the natural healing process of each person. Naturopathic doctors also offer nutritional advice focused on the person as a whole. Naturopaths use dietary supplements, herbal medicine, acupuncture, hydrotherapy, massage, and joint manipulation, as appropriate. Naturopaths encourage people to follow a healthy lifestyle to avoid disease.

Ayurvedic medicine emphasizes treating the mind, body, and spirit as the way to promote wellness. Controlled breathing is just one factor. Other elements of treatment can include diet, exercise, meditation, herbal medicine, and massage. Studies have been done in India on the effectiveness of ayurvedic medicine, but not enough research has been done to prove that this type of medicine helps.

TCM believes that the body contains two opposite forces: yin is the cold, slow and passive force; yang is the hot, fast and active force. Illness occurs when an imbalance occurs between these forces, allowing a kind of life energy (qi, or chi) to become blocked. TCM uses several types of treatment, including acupuncture and heat, Chinese herbs, and massage and body manipulation. Although elements of TCM such as acupuncture and massage are effective in certain cases and for specific health conditions, studies have not verified for sure that TCM as a separate form of medicine works.

Artemisia Annua contains the chemical artemisinin, which researchers used to create drugs for malaria treatment.

St. John's wort has been marketed as a treatment for depression. The NCCIH says that studies on the herb's effectiveness have had mixed results.

A dietary supplement should be regarded as medicine. It can interact with prescription and over-the-counter medicines. Gingko, for instance, can boost the action of blood-thinner medicines (anticoagulants), causing bleeding. Other supplements that have been shown to interfere with medicines include St. John's wort, garlic, glucosamine, ginseng, saw palmetto, and valerian.

Although water-soluble vitamins aren't stored in the body the way fat-soluble vitamins are, they can still cause problems while they are being digested. High doses of vitamin C can cause diarrhea, nausea, and vomiting. High doses of vitamin B-6 can cause nerve damage. Talk with your healthcare provider before taking a dietary supplement, particularly if it's more than a multivitamin.