The impact of the daily consumption of 15 g chicory native inulin on fecal levels of bifidobacteria, stool parameters and quality of life of elderly constipated volunteers was investigated in a randomized, double-blind, controlled versus placebo clinical trial. The impact of supplementation on constipation was assessed with questionnaires on bowel motor function parameters, visual analogue scales on bowel symptoms and quality of life. Fecal bacteria counts were determined at the beginning and at the end of the supplementation. Inulin supplementation led to a significant increase in total fecal bacteria (P < 0.01) and bifidobacteria (P < 0.001) concentrations after 28 days of consumption. Volunteers (n = 25) in the inulin group reported increased satisfaction about digestion (P < 0.01) and reduced defecation difficulties (P < 0.001) during the supplementation. Slight gastrointestinal symptoms (flatulence) were reported but did not lead to discontinuation. Daily supplementation with 15 g inulin improves constipation and quality of life in an elderly population with constipation.