The placebo effect is capable of relieving pain and affective disorders. The mechanism of placebo action is pharmacologic and psychologic, being related to the patient-practitioner relationship and the clinical treatment setting. The placebo effect also occurs with all active or real treatments. The effects of placebos in management of orofacial pain and MPD syndrome have been demonstrated. Placebo effects may account for a third to two-thirds of responses in mandibular dysfunction. Many treatments suggested for management of pain may be acting solely as placebos. Health professionals active in management of pain should understand and use the placebo effect to improve patient care.