Abstract In previous articles evidence was given which suggests that the large fluxes of hydrogen and hydroxylions, observed when water splitting occurs in an ion exchange membrane, originate at charged sites which undergo protonation and deprotonation reactions with water. This paper presents further evidence in support of the theory. It is shown that water splitting can originate at carboxylic acid, phenolic and primary, secondary and tertiary alkyl amino groups. The possibility of the effect occurring in biological membranes is discussed. It is shown that the movement of hydroxyl ions through the membrane zone under the alkali band of Chara corallina might be due to a water splitting process.