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Overview of Complementary and Alternative Medicine

by Steven Rosenzweig, MD

(see also Dietary Supplements.)

Complementary and alternative medicine (CAM) refers to healing approaches and therapies that are not based on principles of mainstream, conventional medicine.

  • Complementary medicine refers to unconventional practices used with mainstream medicine.

  • Alternative medicine refers to unconventional practices used instead of mainstream medicine.

  • Integrative medicine is health care that uses all appropriate therapeutic approaches—conventional and alternative—within a framework that focuses on the therapeutic relationship and the whole person.

CAM has been widely used in the US for decades. Almost 40% of adults use some form of CAM, most often to treat pain or anxiety or to modify cholesterol levels. Use is also common among patients with chronic pain, cancer, hepatitis C, or other intractable conditions. The most frequently used therapies include medicinal herbs (see Dietary Supplements) and other plant-derived supplements (botanicals), mind-body practices, and massage therapy.

Some CAM therapies are now offered in hospitals and are sometimes reimbursed by insurance companies. Some traditional medical schools, including 45 North American medical schools in the Consortium of Academic Health Centers for Integrative Medicine, provide education about CAM and integrative medicine.

Broad, philosophic differences distinguish conventional and alternative approaches to healing (see Differences Between Conventional and Alternative Medicine).

Because patients worry about being criticized, they do not always volunteer information about their use of CAM to physicians. Therefore, it is very important for physicians to specifically ask their patients about CAM use in an open, nonjudgmental way. Learning about patients’ use of CAM can strengthen rapport, build trust, and provide an opportunity to discuss CAM’s benefits and risks. Physicians may also identify and avoid potentially harmful interactions between drugs and CAM therapies or nutritional supplements, monitor patient progress, guide patients to certified or licensed CAM practitioners, and learn from patients’ experiences with CAM.

Differences Between Conventional and Alternative Medicine


Conventional Medicine

Alternative Medicine

Definition of health

Normal function (ie, absence of specific disease or dysfunction)

Optimal balance, resilience, and integrity of the body, mind, and spirit and their interrelationships

Definition of illness

Disease based: Dysfunction of organs or biochemical processes

Symptom and individual based: Imbalance of body, mind, and spirit

Concept of life force

Life processes that involve physical and biochemical events and not a nonphysical life force

A nonphysical life force that unites mind and body, interconnects all living beings, and is the underpinning of health

Understanding of consciousness

Results only from physical processes in the brain

Not localized to the brain; can exert healing effects on the body

Method of treatment

External interventions (eg, drugs, surgery, radiation therapy)

Support and strengthening of patients’ inherent capacity for self-healing


In 1992, the Office of Alternative Medicine in the National Institutes of Health (NIH) was formed to study the efficacy and safety of alternative therapies. In 1998, this office became the National Center for Complementary and Alternative Medicine (NCCAM; see ). Other NIH offices (eg, National Cancer Institute) also fund some CAM research.

There are 3 types of support for CAM therapies:

  • Use over periods of time ranging from decades to centuries

  • Evidence of established physiologic mechanisms of action (eg, modification of γ-aminobutyric acid [GABA] activity in the brain by valerian)

  • Efficacy as shown in clinical trials

A substantial amount of information about CAM is available in peer-reviewed publications, evidence-based reviews, expert panel consensus documents, and authoritative textbooks; much of it has been published in languages other than English (eg, German, Chinese). However, most CAM therapies have not been tested in definitive clinical trials and probably will not be for the following reasons:

  • Industry has no financial incentive to fund research.

  • CAM therapies may be difficult to study using conventional methodology.

  • Manufacturers of CAM products do not have to prove disease-specific efficacy.

Thus, the FDA allows marketing of dietary supplements and use of CAM devices but significantly restricts efficacy claims. Generally, manufacturers of dietary supplements can claim benefit to the body’s structure or function (eg, improves cardiovascular health) but not benefit for treating disease (eg, treats hypertension).


Designing studies of CAM therapies poses challenges beyond those faced by researchers of conventional therapies:

  • Therapies may not be standardized. For example, there are different systems of acupuncture, and the contents and biologic activity of extracts made from the same plant species vary widely (chemical identification and standardization of active ingredients is not considered part of CAM).

  • Diagnoses may not be standardized; use of many CAM therapies (eg, traditional herbal medicine, homeopathy, acupuncture) is based on the patient’s unique characteristics rather than on a specific disease or disorder.

  • Double- or single-blinding is often difficult or impossible. For example, patients cannot be blinded as to whether they are practicing meditation. Reiki practitioners cannot be blinded as to whether or not they are using energy healing.

  • Outcomes are difficult to standardize because they are often specific to the individual rather than objective and uniform (as mean arterial pressure, Hb A 1c level, and mortality are).

  • Placebos may be difficult to devise because identifying the effective component of a CAM therapy may be difficult. For example, in massage, the effective component could be touching, the specific area of the body massaged, the particular massage technique used, or time spent with the patient.

From a conventional research perspective, use of a placebo control is particularly important when subjective outcomes (eg, pain, nausea, indigestion) are used and when disorders that are intermittent, self-limited, or both (eg, headaches) are being studied; such end points and disorders are often the targets of CAM therapies. However, CAM systems interpret placebo effects as nonspecific healing effects that arise out of the therapeutic interaction and are inseparable from specific treatments. In practice, alternative therapies are intended to optimize the patient’s capacity for self-healing (placebo response) as well as treatment-specific effects. Thus, many CAM practitioners strive to enhance the quality of the healing environment and therapeutic relationship. Studying the effective components of a CAM therapy without undermining the integrity of that therapy in a research setting remains a methodologic challenge.


Although the safety of most CAM therapies has not been studied in clinical trials, many of these therapies have a good safety record. Many CAM therapies (eg, nontoxic botanicals, mind-body techniques such as meditation and yoga, body-based practices such as massage) have been used for thousands of years with no evidence of harm, and many seem to have no potential for harm. However, there are some safety considerations, including the following:

  • Use of an alternative approach to treat a life-threatening disorder that can be effectively treated conventionally (eg, meningitis, diabetic ketoacidosis, acute leukemia)—perhaps the greatest risk of CAM, rather than the risk of direct harm from a CAM therapy

  • Toxicity from certain herbal preparations (eg, hepatotoxicity from pyrrolizidine alkaloids, Atractylis gummifera , chaparral, germander, greater celandine, Jin Bu Huan, kava, pennyroyal, or others; nephrotoxicity from Aristolochia ; adrenergic stimulation from ephedra)

  • Contamination (eg, heavy metal contamination of some Chinese and Ayurvedic herbal preparations; contamination of other products, such as PC-SPES and some Chinese herbs, with other drugs)

  • Interactions between CAM therapies (eg, botanicals, micronutrients, other dietary supplements) and other drugs (eg, induction of cytochrome P-450 [CYP3A4] enzymes by St. John’s wort, resulting in reduced activity of antiretrovirals, immunosuppressants, and other drugs), particularly when the drug has a narrow therapeutic index

  • As with any physical manipulation of the body (including mainstream techniques such as physical therapy), injury (eg, nerve or cord damage due to spinal manipulation in patients at risk, bruising in patients with bleeding disorders)

Current alerts about harmful dietary supplements are available at the FDA web site ( ). Historically, the FDA did not tightly regulate the production of dietary supplements. However, new FDA regulations now require compliance with manufacturing practices that guarantee quality and safety of supplements.

To help prevent injuries due to physical manipulations, patients should look for CAM practitioners who graduated from accredited schools and are professionally licensed. Rates of complications are very low when chiropractic or acupuncture is provided by practitioners with full credentials.


Five categories of alternative medicine are generally recognized (see Types of Alternative Medicine):

  • Alternative whole medical systems

  • Mind-body medicine

  • Biologically based practices

  • Manipulative and body-based practices

  • Energy medicine

The name of many therapies only partially describes their components.

Types of Alternative Medicine




Whole medical systems

All-encompassing approaches, including theory and practice (eg, explanation of disease, diagnostics, therapy)


Aims to restore balance within the body

Uses diet, massage, herbs, meditation, therapeutic elimination, and yoga


Based on the law of similars: A substance that causes certain symptoms when given in large doses is used in minute doses to cure the same symptoms


Aims to prevent and treat disease by promoting a healthy lifestyle, treating the whole person, and using the body’s natural healing abilities

Uses a combination of therapies, including acupuncture, counseling, exercise therapy, guided imagery, homeopathy, hydrotherapy, medicinal herbs, natural childbirth, nutrition, physical therapies, and stress management

Traditional Chinese medicine

Aims to restore proper flow of life force (qi) in the body by balancing the opposing forces of yin and yang within the body

Uses acupuncture, massage, medicinal herbs, and meditative exercise (qi gong)

Mind-body medicine

Use of behavioral, psychologic, social, and spiritual techniques to enhance the mind’s capacity to affect the body and thus to preserve health and prevent or cure disease


Uses electronic devices to provide patients with information about biologic functions (eg, BP, muscle activity) and to teach patients to control these functions

Guided imagery

Uses mental images to help patients relax or to promote wellness or healing of a particular condition (eg, cancer, psychologic trauma)


Puts patients into a state of relaxation with attentive and focused concentration to help them change their behavior and thus improve their health


Involves intentional self-regulation of attention or a systematic mental focus on particular aspects of inner or outer experience.

Relaxation techniques

Aim to elicit a psychophysiologic state of hypoarousal by reducing sympathetic nervous system activity and BP, easing muscle tension, slowing metabolic processes, or altering brain wave activity

Biologically based practices

Use of naturally occurring substances (eg, particular foods, micronutrients) to affect health

Biologic therapies

Uses substances naturally occurring in animals (eg, shark cartilage [to treat cancer], S -adenosyl- l -methionine [SAMe], glucosamine [to treat osteoarthritis]) to treat disease

Chelation therapy

Uses a drug to bind with and remove a hypothesized excess or toxic amount of a metal or mineral in the body

Diet therapies

Use specialized dietary regimens (eg, Gerson therapy, macrobiotic diet, Ornish diet, Pritikin diet) to treat or prevent a specific disease (eg, cancer, cardiovascular disorders) or to generally promote wellness


Uses plants and plant extracts to treat disease and promote wellness

Orthomolecular medicine

Uses substances that occur naturally in the body (eg, hormones, vitamins), often in doses higher than the RDA, to treat disease and promote wellness

Manipulative and body-based practices

Focused primarily on the body’s structures and systems (eg, bones, joints, soft tissues)

Based on the belief that the body can regulate and heal itself and that its parts are interdependent


Involves manipulating the spine, other joints, and soft tissue to restore normal spinal neuromuscular function

Also involves prescribing exercises and ergonomic measures


Involves manipulating tissues to promote wellness and to reduce pain and stress

Postural reeducation

Uses movement and touch to help patients become more aware of their body, relearn healthy posture, and move more easily


Involves applying manual pressure to specific areas of the foot that theoretically correspond to different organs or systems of the body

Structural integration

Involves manipulating and stretching the fascia to reestablish healthy bone and muscle alignment

Energy medicine

Manipulation of the body’s energy fields (biofields) with the intent to affect health

Based on the belief that a universal life force or subtle energy resides in and around the body


Stimulates specific points on the body, usually by inserting thin needles into the skin and underlying tissues to unblock the flow of qi along energy pathways and thus restore balance in the body

External qi gong

Involves master healers using the energy of their own biofield to bring the patient’s energy into balance


Placing magnets on the body to reduce pain

Pulsed electrical field

Placing injured body parts in an induced electrical field to facilitate healing


Involves practitioners channeling energy through their body and into a patient’s body to promote healing

Therapeutic touch

Uses the therapist’s healing energy, usually without touching the patient, to identify and repair imbalances in the patient’s biofield

RDA = recommended daily allowances.

Resources In This Article

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