摘要:The prevalence of immunologically mediated diseases including allergies in Western countries has increased significantly during the past 30 - 50 years, in contrast to what has happened in the former socialist countries. An altered intestinal microbial stimulation may be one reason for a changed immune response. One possible explanation is that there could be quantitative and/or qualitative differences between the establishment of a functionally active intestinal microflora in infants in Western countries leading to different maturation of the enterocytes. The aim of this study was to investigate the function of the metabolically active intestinal microflora in cohorts of 43 healthy infants from Estonia and 25 healthy infants from Sweden during their first year of life by studying the short-chain fatty acid (SCFA) profile in faecal samples. The SCFA profiles differ significantly during the first month of life. At 1 month of age, the Swedish infants have significantly higher amounts of SCFAs in their faeces, and all acids except iso-butyric acid were present in more Swedish than Estonian infants. Moreover, there was a quicker ‘shift to the right’ with regard to the presence of the higher acids (C<sup>4</sup>-C<sup>6</sup>) in the Swedish infants. Our results show significant differences in a major microbial intestinal function between Estonian and Swedish infants during their first month of life. Possible causes for these findings and the impact on the host of the diverse SCFA profiles is discussed. These findings have created a background for ongoing studies on allergy and atopy in infants. Key words: Children, intestinal flora, allergy, short-chain fatty acids, microflora-associated characteristics.