Neuropathic pain is caused by functional abnonnalities of structural lesions in the peripheral or central nervous system, and occurs without peripheral nociceptor stimulation. Trigeminal neuropathy always pose differential location difficulties as multiple diseases are capablc of producing them: they can be the result of traumatism, tumors, or diseases of the connective tissue, infectious or demyelinating diseases, or may be of idiopathic origin. There are a number of mechanisms described as causing neuropathy. They can be described as ectopic nerve activity, neuroma, ephatic trasmission, change of sodium channel expression, sympathetic activity, central sensitization, and alteration in central inhibition systems. More than I mechanism may be active to create individual clinical presentations. In order to provide better pain control, the mechanism-based approach in treating neuropathic pain should be familiar to physicians.