Changes in the excitability of the liverwortConocephalum conicumL. caused by inhibitors of ionic channels and phosphorylation uncouplers, were examined. Action potentials were triggered by electrical and light stimuli. Tetraethylammonium chloride, an inhibitor of K+channels, completely blocked the ability to generate action potentials. Excitability also disappeared under the influence of MnCl2and LaCl3, inhibitors of Ca2+channels. The participation of Ca2+and K+in the electrogenesis of action potentials inC. conicumis discussed. Treatment with phosphorylation uncouplers induced a gradual disappearance of the metabolic component of the resting potential. It was accompanied by some series of excitations, numbering from several to over a dozen impulses characterized by decreasing amplitudes, after which the organism became totally unexcitable. Dicyclohexylcarbodiimide an inhibitor of H+‐ATPase, also caused depolarization of the transmembrane potential and disappearance of excitability. The results indicated the participation of a metabolic component in the generation of action potentials inC. conicu