Histopathological changes induced by intrahippocampal injections of low doses of kainic acid (17.5 ng/site) were investigated in rats. Kainic acid produced a selective loss of CA3 pyramidal and hilar neurons. The development of kainic acid-induced neuronal injury was not accompanied by any detectable loss of histologically demonstrable zinc as assessed by means of a modified Timm's sulphide-silver method. It is suggested that the selective injury of hippocampal neurons induced by kainic acid is not contingent on the release of zinc from mossy-fiber terminals.