Burning mouth syndrome (BMS) is characterized by the presence of burning 
sensation of the oral mucosa in the absence of clinically apparent mucosal 
alterations. It occurs more commonly in middle-aged and elderly women and often 
affects the tongue tip and lateral borders, lips, and hard and soft palate. In 
addition to a burning sensation, the patients with BMS may also complain 
unremitting oral mucosal pain, dysgeusia, and xerostomia. BMS can be classified 
into two clinical forms: primary and secondary BMS. The primary BMS is essential 
or idiopathic, in which the organic local/systemic causes cannot be identified 
and a neuropathological cause is likely. The diagnosis of primary BMS depends 
mainly on exclusion of etiological factors. The secondary BMS is caused by 
local, systemic, and/or psychological factors; thus, its diagnosis depends on 
identification of the exact causative factor. When local, systemic or 
psychological factors are present, treatment or elimination of these factors 
usually results in a significant clinical improvement of BMS symptoms. Vitamin, 
zinc, or hormone replacement therapy has been found to be effective for reducing 
the oral burning or pain symptom in some BMS patients with deficiency of the 
corresponding factor. If patients still have the symptoms after the removal of 
potential causes, drug therapy should be instituted. Previous randomized 
controlled clinical trials found that drug therapy with capsaicin, alpha-lipoic 
acid, clonazepam, and antidepressants may provide relief of oral burning or pain 
symptom. In addition, psychotherapy and behavioral feedback may also help 
eliminate the BMS symptoms.