['Colonisation of the human colon starts immediately after birth. Bacterial composition is substantially influenced by the type of feeding. During weaning, microbiota diversifies considerably to finally approach the composition of that of adults. The aim of this study was to investigate the ability of colonic microbiota obtained from different age groups to ferment resistant starch (RS).', 'Faecal samples of breast-fed and formula-fed infants, infants at weaning, adults and elderly subjects were used as inocula. Fermentation experiments were performed by applying a standardised in vitro batch method. Fermentability was established by measuring both metabolite production and substrate degradation. An RS type 3 (RS-3) was used as substrate; its behaviour was compared with that of lactulose (positive control), whereas inoculum without substrate was used as negative control.', 'Overall fermentation patterns clearly showed that the human microbiota of all age groups is able to degrade lactulose. In contrast, RS-3 was found resistant to the attack by microbiota of both breast-fed and formula-fed infants. Bacteria collected from infants at weaning were able to degrade RS-3 completely, but slower compared with adults. With increasing age, RS-3 fermentation was observed to be slightly retarded again.'] Does human faecal microbiota develop the ability to degrade type 3 resistant starch during weaning?