 Data which support the hypothesis that BMS is a neuropathic pain condition include amongst others a recent clinically controlled study that has shown up-regulation of TRPV1-positive nerve fibres in tongue mucosa in patients with BMS. The vanilloid receptor-1 TRPV1 is a voltage-dependent cation channel expressed by the unmyelinated C-nociceptive nerve fibres and the receptor may be activated by capsaicin from chili peppers, heat and H. Capsaicin binds to the TRPV1 receptor causing depolarization of the C-nociceptors. Prolonged activation of these neurons by capsaicin depletes pre-synaptic substance P and makes them unable to report pain. 