Biofeedback is a type of complementary and alternative medicine (CAM) that analyses the patient's bodily processes such as heart rate, blood pressure, sweating, muscle tension and skin temperature. The practitioner gives information to the patient in real-time to make the patient aware of his or her current status and conscious control of the physiological activities.

Biofeedback works in such a way whereby the patient can have access to this physiological information almost immediately and therefore the patient can control some of the processes that he or she thought was out of their control before i.e. automatic.

Interest in biofeedback and its various processes was kicking around in the 1960s but nothing was done for a few decades until most recently whereby people are taking a renewed interest in the subject. This is partially to do with the renewed interest in complementary and alternative medicines in general. ADHD is being treated recently by neurofeedback and muscle tension feedback is now being studied more worldwide being used for incontinence disorders. Small biofeedback machines that can be used in ones house are becoming more and more popular in people's homes around the world.

Electromyogram or more commonly known as EMG is the most popular of the biofeedback measuring tools. It uses sensors in the form of electrodes or other such methods to calculate muscle tension. It is used in a way whereby one learns to recognize the feeling early on and therefore the patient can learn to control this muscle without creating unnecessary tension. EMG is used for relaxation and helping patients to control muscles without discomfort. It is used for backaches, neck pain, headaches and teeth grinding. Some stress-related illnesses may also be treated using EMG.

Biofeedback uses EMG sensors attached to ones fingers or feet to measure skin temperature. Stress can induce a lower body temperature and therefore the sensors can pick up on this stress early on. It can help conditions such as Raynaud's disease and reduce migraine occurrences. A temperature drop is caused by blood vessels being narrowed in their walls thus creating a colder climate for the skin.

The sensors measure the amount of sweat gland activity when responding to anxiety. It this manner, biofeedback can be useful for treating not only physical conditions, but emotional ones too such as anxiety, stuttering and phobias. Lie detector machines commonly use this method and it is now being incorporated into other fields of study such as hypnotherapy and psychotherapy whereby the meters can calculate emotional arousal rather than just by the practitioner making an estimated guess.

Electroencephalography or more commonly known as EEG monitors brain wave activity in conjunction with different mental states of humans such as relaxation, calmness, wakefulness, light and deep sleep. EEG machines tend to be quite expensive to purchase and run and therefore this type of method is not too common amongst biofeedback.

The origins of biofeedback can be credited to Neal Miller who was a neuroscientist that studied and worked at Yale University. He stumbled upon the idea when he was conducting different tests and experiments on animals, in particular with rats. He found that if he manipulated the rat's pleasure center with electricity, the rats would have more control over different types of movement such as heart rate and brainwave activity. This was the basis to suggest that such activity could be regulated going against the previous idea of such activities being totally controlled by the automatic nervous system.

Criticisms against biofeedback are not so much criticisms but more useful suggestions. For example it is widely said in the medical world that neurofeedback used for treating attention deficit disorders is promising rather than proven whereby the criticism is rather a positive estimate.