The importance of intermolecular forces in proton-transfer reactions is considered, with special reference to the theories of Dogonadze and his collaborators. It is concluded that the configuration which these theories demand in order to account for observed isotope effects and other phenomena are unrealistic, being effectively excluded by the high repulsive energies involved. An alternative treatment, in which a tunnel correction is applied to the activated transfer of the proton, is consistent with our knowledge of isotope effects and intermolecular forces.