The need for careful research on complementary and alternative health practices remains compelling. Tens of millions of Americans are spending $34 billion per year (mostly out-of-pocket) on a variety of complementary approaches, most often without any solid evidence about safety or usefulness.

The opportunities to make real differences in some very challenging health issues are equally compelling. After a decade of mainly exploratory research across a broad array of interventions, practices, products, and disciplines, emerging scientific evidence points toward the need for more targeted investment in selected complementary approaches.

Probiotics are live microorganisms (in most cases, bacteria) that are similar to beneficial microorganisms found in the human gut. They are also called "friendly bacteria" or "good bacteria." Probiotics are available to consumers mainly in the form of dietary supplements and foods.

As with any treatment, it is important to consider safety before using complementary health products and practices. Safety depends on the specific therapy, and each complementary product or practice should be considered on its own.

Mind and body practices such as meditation and yoga, for example, are generally considered to be safe in healthy people when practiced appropriately. Natural products such as herbal medicines or botanicals are often sold as dietary supplements and are readily available to consumers; however, there is a lot we dont know about the safety of many of these products, in part because a manufacturer does not have to prove the safety and effectiveness of a dietary supplement before it is available to the public.

Depression is a medical condition that affects nearly 21 million American adults each year, according to the National Institute of Mental Health. Mood, thoughts, physical health, and behavior all may be affected. Among the common symptoms of depression are persistent sad, anxious, or "empty" feelings; feelings of hopelessness, guilt, and/or worthlessness; restlessness or irritability; fatigue; difficulty concentrating; insomnia; overeating, or loss of appetite; and/or thoughts of suicide.

Many people with a depressive illness never seek treatment. But the majority, even those with the most severe depression, can get better with treatment. Depression can be treated effectively with conventional medicine, including antidepressants and certain types of psychotherapy.

Some people turn to complementary health products and practices for depression, including the dietary supplement St. John's wort; however, no complementary approach has been proven effective for the long-term treatment of depression. This issue provides information on "what the science says" about the effects of complementary health products for depression, including the dietary supplements omega-3 fatty acids, St. John's wort, valerian, as well as other complementary practices such as massage, relaxation techniques, and yoga.

Headaches are one of the most common forms of pain. For some people a headache may be a minor irritation once or twice a year, while others can suffer disabling pain on an almost daily basis. Researchers are studying treatments for different types of headaches, including a number of complementary and alternative medicine (CAM) therapies. This fact sheet provides basic information on headaches, summarizes research on the effectiveness and safety of selected complementary and alternative practices for headaches, and suggests sources for additional information. If you are considering a complementary and alternative therapy for headaches, this information can help you talk to your health care provider about it.

St. John's wort is a plant with yellow flowers whose medicinal uses were first recorded in ancient Greece. The flowering tops of St. John's wort are used to prepare teas, tablets, and capsules containing concentrated extracts. Liquid extracts and topical preparations are also used. Today, St. John's wort is used by some for depression, anxiety, and/or sleep disorders.

This fact sheet provides basic information about cinnamon—common names, what the science says, potential side effects and cautions, and resources for more information.

Cinnamon comes from the bark of trees native to China, India, and Southeast Asia. A popular cooking spice in many cultures for centuries, cinnamon also has a long history of use as a folk or traditional medicine. For example, many ancient societies used cinnamon for bronchitis. Additional folk or traditional uses include gastrointestinal problems, loss of appetite, and control of diabetes, as well as a variety of other conditions.

Cinnamon bark is used to make powders, capsules, teas, and liquid extracts. Although there are many kinds of cinnamon, Ceylon cinnamon (sometimes referred to as "true" cinnamon) and cassia cinnamon (also known as Chinese cinnamon) are the most familiar.

Headaches are one of the most common forms of pain. More than 45 million Americans have headaches severe enough to require the help of a health care professional. Headaches occur when pain-sensitive nerve endings around the scalp, in the blood vessels that surround the skull, in the lining around the brain, and in other areas around the head send impulses to the part of the brain that interprets pain signals from the rest of the body. Some headaches are related to tender spots in head, neck, and shoulder muscles.