Background:The role of milk polyamines in the development of the gastrointestinal tract of human infants is presently unknown. Polyamine concentrations are higher in human milk than in infant formulas. The aim of the present study was to gather data on luminal polyamines by measuring gastric fluid and fecal polyamine concentrations in premature infants during the postnatal period. We further compared gastric fluid polyamine concentrations with those reported for milk and looked for possible relationships between luminal polyamine concentrations, age, and growth rate.Methods:High-performance liquid chromatography was used for the measurement of polyamine concentrations in both fecal and gastric fluid samples.Results:Ninetieth centiles for gastric polyamines during the first week were 62, 28, 82, and 14 μMfor putrescine, spermidine, spermine, and cadaverine, respectively. These values are higher than those reported for human milk and infant formulas. Polyamine concentrations were unrelated to either age or growth rate. Ninetieth centiles for fecal polyamines during the first week were 7668, 5176, 53, and 75 μMfor cadaverine, putrescine, spermidine, and spermine, respectively.Conclusions:Fasting gastric fluid polyamine concentrations in premature infants are higher than those reported for either human milk or infant formulas. The high fecal cadaverine and putrescine concentrations are probably of bacterial origin.