The aim of this study was to assess the influence of growth hormone (CH) in sepsis on the immune system represented by the circulating TNF-levels and the neutrophil leukocytes phagocytic capacity and respiratory burst, 22 piglets were randomized to 3 groups; pretreatment with CH (16 IU) before sepsis (rr = 8), non-treated septic controls (n = 8), and non-septic controls (n = 6), Sepsis was induced by a standardized infusion of live E. coli, TNF was measured by a cytotoxic bioassay, while neutrophil function tests were carried out by flowcytometric assays. In brief, phagocytosis was evaluated by the neutrophils' ability to ingest FITC-labelled (fluorescein isothiocyanate) E, coli and intracellular release of oxygen metabolites was detected by the oxidation of 2',7'-dichlorofluorescin (DCFH) to the fluorescent 2',7'-dichlorofluorescein (DCF). Our data show a suppression of phagocytosis in the CH-treated group before sepsis; however, when challenged with Cram-negative bacteria, the phagocytic capacity was similar to that of the non-treated animals. The serum levels of TNF in the non-treated septic control group were twice the levels of those in the GH-treated group, 65.7 pg/ml (septic controls) vs 32.8 pg/ml (GH), Pretreatment with a single dose of GH few hours prior to sepsis does not seem to entail any further imbalance of the neutrophil function in sepsis. Lowering of the circulating TNF-levels is a presumptive favourable effect of CH in sepsis.