The present invention comprises alkylpiperazine- and alkylhomopiperazine carboxylates and their derivatives, methods for their preparation and the therapeutic use thereof as fatty acid amido hydrolase (FAAH) enzyme inhibitors. These derivatives exert various pharmacological activities by interacting, inter alia, with cannabinoid and vanilloid receptors. By inhibiting the metabolic activity of the FAAH enzyme, compounds often responsible for the onset of disease and other pathological conditions are not generated and the incidence of the disease is greatly reduced.