Inflammatory pain is mediated from the periphery by a specialized subgroup of nerve fibers, the nociceptors. The nociceptive nerve endings undergo sensitization and excitation when stimulated with inflammatory agents. It will be shown that a multitude of substances cooperates in this process. Since nociceptive nerve endings are too small to be approached directly with the methods of intracellular electrophysiology, one has to extrapolate to the membrane channels and intracellular processes mediating nociceptor sensitization from studies on the perikarya of sensory ganglion cells. Sustained inflammation induces profound plastic changes in peripheral and central neurones leading to an altered excitability.