The behaviour of zinc and zinc oxide in 5.3 M KOH in the presence of alkaline earth oxides, SnO, Ni(OH)(2) and Co(OH)(2) was examined by cyclic voltammetry. The influence of the alkaline earth oxides was compared with additives of established effects (Bi2O3, LiOH, Na2CO3 and CdO). The alkaline earth oxide each exhibits a distinct behaviour towards zincate. Whereas, a single process of interaction with zincate was shown by CaO; two modes of reaction were obtained with SrO and BaO. Solid solution formation was noticed with BeO and MgO. The other additives forming solid solution with ZnO were CdO, SnO. The ionic sizes of Ni(OH)(2) and Co(OH)(2) allow solid solution formation with Zn(OH)(2). Both Bi2O3 and Na2CO3 enter into complexation with zincate. LiOH forms two distinct zincates, of which one is an oxo zincate leaching the 'hydroxyl' functionality. Cyclic voltammetry revealed the deposition of the oxide/hydroxide additives as metal prior to the onset of zinc deposition and the potential range for this additive metal deposition is almost the same for different additives (SnO, CdO, Ni(OH)(2)). The beneficial action of these additives to zinc alkaline cells is associated with a substrate effect. The implication of this electrocatalytic deposition of metals on a zinc oxide electrode is also discussed.