When you were a child and sprained an ankle or came down with the flu, you probably visited a pediatrician to soothe your symptoms. As an adult, you most likely visit your primary care physician for everything from sinus pain to migraines, from asthma to diabetes. But now your friends are suggesting treatments you've never heard of — everything from homeopathy to ayurveda, from herbs and supplements to yoga and acupuncture.

What are these complementary and alternative therapies you've been hearing about? Are they safe? Will they work? Educate yourself before starting any new therapy, and always tell your doctor which ones you're trying.

No one standard definition for complementary and alternative medicine (CAM) exists. But in general, complementary and alternative medicine refers to practices that aren't integral parts of conventional medicine, according to the National Center for Complementary and Alternative Medicine. What is or isn't considered complementary and alternative changes constantly as an increasing number of treatments undergo rigorous study and are proved to be effective or not.

Though the two terms are often grouped together, complementary and alternative treatments aren't necessarily the same thing. Complementary treatments are often thought of as treatments that are used along with the conventional therapies your doctor may prescribe, such as using tai chi or massage in addition to prescription medication for anxiety.

Alternative approaches are generally thought of as being used instead of conventional methods. For example, this might mean seeing a homeopath or naturopath instead of your regular doctor.

Many CAM practitioners base their work around a few basic philosophies. Some of these are similar to what your conventional doctor might do, while others are different. Here are some of the basic philosophies:

• Your body heals itself. CAM practitioners see themselves as facilitators. To them your body does all the healing work, and you only need treatment that encourages your natural healing processes. Rather than treating symptoms of a cold, a practitioner might prescribe something to boost your immune system.
• Prevention is key. Complementary and alternative medicine stresses prevention. Your practitioner won't necessarily just want to see you when you're sick, and the kind of treatment you receive focuses on helping your body keep itself healthy.
• Learning and healing go hand-in-hand. Your CAM practitioner views herself or himself as a teacher and mentor who offers guidance. To her or him, you are the one who does the healing.

Although you may have just heard about some of these treatments, much of what's referred to as complementary and alternative medicine isn't new. Many therapies, such as tai chi or ayurveda, have been practiced for thousands of years.

To make sense of the many therapies available, it might help to look at them in the five broad categories that the National Institutes of Health uses for classification:

Healing systems
Healing systems are complete sets of theories and practices. A system isn't just a single practice or remedy — like massage — but many different practices that all revolve around a philosophy or lifestyle, such as the power of nature or the presence of energy in your body. Many complementary and alternative healing systems developed before the conventional Western medicine commonly used in the United States.

The ayurveda system, for instance, dates back 5,000 years to ancient India. Ayurveda practitioners base their treatments around the idea that people differ from each other physically and psychologically, so each treatment will be different. Three people with pain in their shoulder will each receive different treatment. A practitioner classifies you by the combination of three energies (doshas) in your body. According to ayurveda theory, illness results when your energies get out of balance. Your treatments involve sense therapies, which use your five senses — sight, sound, touch, taste and smell — to balance your energy. You might need aromatherapy, a special diet, color therapy, sound therapy or massage. Ayurveda is best-known for preventing disease by promoting balance through nutrition, exercise, herbs, meditation and other treatments.

Other systems aren't as ancient. Homeopathy was developed in Germany about 150 years ago. A homeopathic pratictioner determines your treatment based on all of your symptoms, both physical and emotional. You and your neighbor may both have colds, but if you also have a headache then your treatment is going to be different from your neighbor's. Treatments often consist of a very small amount of a substance — plant, animal or mineral — that, in larger doses, gives a healthy person similar symptoms. A homeopathic remedy for your nausea might be a diluted solution of ipecac root (ipecacuanha) because in larger doses it's been used to induce vomiting. Practitioners frequently schedule a visit about a month later to gauge how the initial dose is working.

Naturopathic doctors recommend the least-invasive treatments and procedures to help you feel better. Surgery is always a final option. Most of their recommendations are based on such natural therapies as proper nutrition, exercises and herbal medicines. Naturopathic doctors go through extensive training, much like conventional doctors, and use some of the same exams and tests to diagnose your condition. But unlike conventional doctors, they can't perform major surgery and don't practice emergency medicine. Naturopathy relies on your body to do its own healing, and therapies are designed to assist that process.

Traditional Chinese, Asian, Pacific Islander, Native American and Tibetan practices also fall into the healing systems category.

Mind-body connections
Mind-body techniques strengthen the communication between your mind and your body. CAM practitioners believe these two systems must be in harmony for you to stay healthy. If your mind and body aren't communicating, you could get sick. The methods in this category can be used to maintain your mind-body connection or to strengthen the connection if you're already sick.

Mind-body connections enhance your mind's ability to control and regulate symptoms of distress or illness. Your CAM practitioner might recommend these methods if your mind is keeping your body from being healthy, such as when you're feeling stressed out.

Meditation is one means of enhancing the mind-body connection. During a meditation session you sit still and focus on something, maybe a word or your deep breathing. This is also called mindfulness, and it relaxes your body by slowing your breathing and heart rate, while decreasing your muscle tension. This deeply relaxed state helps you manage pain and reduce stress and anxiety.

Yoga, on the other hand, uses postures and meditation to enhance your mind-body connection. It can also improve your flexibility, strength and balance. A typical yoga session incorporates four elements: breathing, relaxation, poses and meditation. Dozens of poses exist, and each is intended for a specific purpose, such as improving strength or posture, or relaxing organs. At the same time, yoga encourages you to think about your movements, which relaxes you and clears your mind.

Biofeedback teaches you to use your mind to control your body. Through practice, you can learn to control your heart rate, skin temperature, blood pressure and muscle tension, along with many other body functions. At a biofeedback session, your practitioner puts electrodes on your body and connects them to monitors. The monitors tell you when your temperature, heart rate or other measure goes up or down. It's hard to say why biofeedback works, and many people who've tried it can't explain how they're able to control their bodies. One theory is that you become in sync with the monitors and intuitively learn what triggers your body's reactions. But once you learn to control these body functions in a clinical setting, you can often control them on your own.

You can strengthen your mind-body connections through several other techniques, including prayer, hypnosis, relaxation, and art therapies, such as poetry, music and dance.

Dietary supplements and herbs
These treatments use ingredients found in nature. Examples of herbs include ginseng, ginkgo and echinacea, while examples of other dietary supplements include selenium, glucosamine and SAMe.

Herbal treatments have been used for thousands of years. Many of today's conventional medicines began as folk medicines, including digoxin, which treats congestive heart failure, and quinine, which treats malaria. Many people trust in herbal medicine because of its long history, and others like its use of "natural" products. Remember, though, that natural doesn't mean that herbs can't hurt you.

If your doctor or practitioner prescribes herbal remedies, your treatment could come in a few different forms:

• Teas made by pouring boiling water over fresh or dried herbs and allowing them to steep.
• Liquids made by boiling herbs in water, then using the concoction to make oils or syrups.
• Solids such as powders, tablets and capsules.

People take herbs and supplements for a variety of reasons. Some people take echinacea if they have a cold or the flu. You might turn to ginseng to boost your energy, increase sexual stamina, reduce stress or combat the effects of aging, such as memory loss.

Herbal treatments aren't regulated nearly to the degree other drugs are, so little proof exists that these remedies can help you. Hundreds of herbs and supplements are available. If you decide to take an herb, read the label carefully and follow the directions. Some herbal supplements contain ingredients that don't mix well with your prescriptions or over-the-counter drugs. And others can increase your risk of bleeding during surgery. Keep track of what you take and tell your doctor.

Manipulation and touch
These methods use human touch to move or manipulate a specific part of your body. A chiropractor, for instance, will manipulate your spine using her or his hands. And a massage therapist will use her or his hands to massage your sore muscles.

Chiropractors use a hands-on type of adjustment called spinal manipulation. Most people visit chiropractors for back pain. According to chiropractic theory, misaligned vertebrae can restrict your spine's range of motion and affect the nerves radiating from your spine. In turn, the organs that depend on those nerves may function improperly or become diseased. Chiropractic adjustments aim to realign your vertebrae, restore range of motion and free up your nerve pathways.

Your chiropractor may ask you questions about your pain and examine your spine. This helps her or him decide where your spine needs manipulation. To manipulate your spine, your chiropractor puts pressure on your back using her or his hands. You'll feel a pinching sensation and sometimes hear a popping noise, which is normal. You'll usually have your spine manipulated two to five times a week for the first couple of weeks and fewer times a week after that until your pain goes away.

Osteopathy uses manipulation to treat problems with your bones and muscles. Doctors of osteopathy (osteopath or D.O.) undergo training that is largely the same as that of conventional doctors, but with additional training and emphasis on using manipulation. Osteopathic manipulations are much like chiropractic manipulations. An osteopathic doctor uses his or her hands to feel the area where you're experiencing pain. He or she might move your arm, leg, neck or other body part to see if your range of motion is reduced. The adjustment can vary — at least 30 different types of adjustment are practiced. An osteopathic doctor might apply pressure to your affected area, and you'll feel a pinching sensation or hear a popping sound. In other manipulations, an osteopathic doctor might hold your arm, leg or affected body part in place or move it back and forth in a precise manner. It might seem like nothing is happening when he or she does this, but after a few treatments you should begin to notice a difference in how you feel.

Massage involves the kneading, stroking and manipulation of your body's soft tissues — your skin, muscles and tendons. It's used to relieve muscle tension and stress and promote relaxation. Your massage will vary depending on the rhythm, rate, pressure and direction of these movements. A Swedish massage uses long, gliding strokes to promote relaxation and improve your circulation. A deep tissue massage uses slow strokes, but more pressure than a Swedish massage, to reach deeper layers of your muscle. During most massages, you'll need to take off your clothes and lie down on a padded table, though some massages can be done in a chair with your clothes on. Most massages last 30 minutes to an hour. About 100 different varieties of massage exist, and your doctor or massage therapist can help you decide which is best for you.

You might be familiar with other manipulation therapies. They include craniosacral therapy and acupressure.

Restoring natural energy forces
Some practitioners believe an energy force flows through your body. You can't see this energy, but if its flow is blocked or unbalanced you can become sick. Different traditions call this energy by different names, such as chi, prana and life force. Unblocking or re-balancing your energy force is the goal of these therapies, and each one accomplishes that differently.

Acupuncture, for example, is intended to restore your natural energy (chi) through the insertion of needles into points along energy pathways (meridians) in your body. The needles help stimulate the energy flow. Your practitioner begins by asking questions to gauge what treatment you'll need. You might find some of the questions seem odd, such as "What colors do you prefer?" But this goes into deciding what treatment you'll get. You'll be asked to lie on a table during the treatment. And depending on your reasons for seeking acupuncture, you'll have one or several hair-thin needles inserted into your skin. Some go as deep as 3 inches, depending on where they're placed in your body and what the treatment is for. The needles usually are left in for 15 to 30 minutes. You and your practitioner decide how many treatments you'll need and how often you'll need them.

Practitioners of therapeutic touch believe that they can use their own energy forces to heal your energy force. Practitioners remove disturbances in your energy flow by moving their hands back and forth across your body. During a therapeutic touch session you might lie down or sit in a chair. Sometimes practitioners will touch you, while other times they may place their hands just above your skin. Their hands sense energy disturbances in your body through hot and cold sensations, and sometimes they can feel your tenseness or pain. You might feel your practitioner's energy as a warm, soothing and relaxing sensation.

Reiki also uses touch to transfer healing energy forces. This Japanese healing technique builds off of your natural instinct to touch when you or others experience pain. You instinctively touch your arm if you feel a cramping sensation, and you might also feel a need to touch someone else who is experiencing physical or emotional pain. In a Reiki session you typically wear loose-fitting clothing and lie down on a padded table. Reiki therapists gently lay their hands on your body, starting with your head. Through their hands, Reiki therapists transfer healing energy to your body. You might feel warm or even hot sensations from the therapist's hands. A typical session lasts an hour and leaves you feeling relaxed.

Other forms of energy healing include magnet therapy, polarity therapy and light therapy.

Before modern medicine, if you were sick, you turned to folk medicine or shamans for healing. But in the late 1800s that changed. Scientific, fact-based medicine became more popular. One reason was that your doctor had to be licensed. If you practiced folk medicine, you couldn't be licensed because those therapies weren't rooted in science and reason. Medical schools no longer taught complementary and alternative medicine, so doctors didn't prescribe those treatments. This caused rifts between CAM practitioners and conventional doctors and, for many years, the two stayed completely separate.

But in the 1970s, interest in complementary and alternative therapies began to spread. Reasons range from a realization that modern medicine can't cure everything to a willingness to try new things.

You might hesitate to talk to your doctor about CAM treatments because you're afraid he or she will automatically dismiss those options. It's true that some doctors may not want to discuss CAM therapies, but as many as half the doctors in the United States refer people to CAM practitioners. Your doctor may, in fact, be willing to discuss these options with you.

Regardless of your doctor's opinion of complementary and alternative medicine, make sure you let him or her know what treatments you're using. By communicating carefully with your doctor, he or she can help provide you with information about risks and benefits so that you can make informed decisions regarding these treatments.

With so many studies on new drugs available, you may be wondering why studies about complementary and alternative medicine are so scarce. Reasons include:

• Research is expensive. When a drug company gives money for a study, it hopes to recover that money so it can continue doing more studies. That drug company can patent a new drug and make money from the sales. But most CAM treatments can't be patented because it's hard to claim you're the owner of a therapy that's been used for thousands of years, and it's hard to patent an herb that you can grow in your backyard. But because so many people are interested in trying CAM, the National Institutes of Health and some medical associations are working to raise more funding for this type of research.
• CAM treatments aren't a formula. In a typical research study, participants take the same treatment for a condition. But complementary and alternative practitioners prescribe different treatments for people with the same condition. It's hard to draw overall conclusions from these individual therapies.

Before choosing a treatment, evaluate the benefits and risks. Talk with your doctor about the complementary and alternative therapies you're interested in. Keep in mind that some therapies may help you, others may not, and some could even harm you. Exaggerated claims are not uncommon. Use your best judgment and talk to your doctor about any concerns you might have.