Currently, research is being performed in the area of nonsurgical and nonchemical means for influencing the body's threshold for pain. Today, transcutaneous electrical nerve stimulation (TENS) is being widely used for this purpose. Application of this treatment can be confusing, however, because determining such things as selection of the proper intensity, frequency, and duration of doses, and proper electrode placement may be difficult. While patients stimulated with low-frequency TENS and with conventional high-frequency TENS both experience pain relief, a controversy exists over the pulse width. A sound knowledge of etiology, location, and character of pain is essential in selecting stimulation sites. Experiments in applying TENS to acupuncture points have indicated that this method of locating stimulation points can be effective. (JD)