The specific influence of malnutrition on the pathophysiologic changes induced by chronic alcoholism is controversial. In an attempt to determine and demarcate the effects of protein malnutrition from those produced by alcoholism and to evaluate the precise effect of alcohol per se on cytochemical and ultrastructural properties of rat polymorphonuclear neutrophil (PMN) granules, we investigated the influence of chronic protein malnutrition or chronic alcoholism alone and in combination, in rats. After a 4 month experimental period various PMN properties, such as cytochemical, morphometrical and ultrastructural, as well as neutrophil functions were studied. It was found that the degree of damage of PMNs induced either by ethanol or protein malnutrition alone was similar whereas their combination led to worsening of all markers of PMN functional ability. Ultrastructural changes of neutrophil granules including reduction, redistribution and atypical accumulation as well as appearance of autophagic vacuoles, confirmed their alteration which was emphasised by the additive pathophysiological interaction of alcoholism and chronic hypoprotein malnutrition.