Background Burning mouth syndrome (BMS) is a chronic, intraoral burning sensation seen mainly in middle-aged and post-menopausal females, without identifiable oral lesions or abnormal laboratory findings, but often associated with psychogenic disorders such as depression. The latter can have a range of causes, including hormonal. Objective Since there may be connections between BMS, psychogenic changes, hormonal changes and taste abnormalities , we have examined aspects of taste and thyroid function.. Patients and methods We selected 50 patients with BMS (study group) and 50 healthy subjects (control group) and analysed their ability to taste bitter, acid and spicy substances and analysed their thyroid function and Undertook thyroid echography. Results Taste sensation was normal in all controls. However, 30 of the patients with BMS reported ageusia for bitter taste and 2 had ageusia for acid. The use of pepper sauce ( Tabasco®) (spicy substance) produced a strong burning to the tongue in 28 patients of the BMS group but only in 10 controls. No control patients showed abnormality of thyroid function or echograpic abnormality. Five patients in the BMS group had biochemical evidence of hypothyroidism, 4 patients had raised levels of thyroid autoantibodies and, of the 41 remaining BMS patients, most (34) had thyroid echographic changes indicative of nodularity. Conclusions Hypothyroidism may be responsible for a negative influence on taste and consequent increase in trigeminal sensorial sensation (tactile, thermal and painful sensation).