The aim of the study was to determine, in a group of patients with therapy-resistant burning mouth syndrome (BMS), the possible deficiency of vitamins B₁, B₂, and B₆ and the effect of proper vitamin replacement therapy. Sixteen individuals, aged 47 to 81 years, participated in the study. All underwent a base-line examination comprising anamnestic information, subjective assessment of symptoms, dietary registration, salivary analysis, and serum analysis of thiamine (B₁), riboflavine (B₂), and pyridoxine (B₆). Fifteen individuals had low thiamine and/or riboflavine levels in accordance with suggested levels in the literature and were given replacement therapy. No effect on BMS of vitamin replacement therapy or placebo therapy could be demonstrated.