The study aims to evaluate the effects of short-chain fructo-oligosaccharides on the frequency and consistency of stools in subjects with functional constipation.

This randomized, placebo-controlled, double-blind study aims to evaluate the effects of short-chain fructo-oligosaccharides on the frequency and consistency of stools in subjects with functional constipation.

Inclusion Criteria:

• functional constipation according to ROME III criteria with 3 or less than 3 stools per week
• BMI between 18 and 32kg/m², limits included
• Subjects who do not usually eat high-fibre foods
• Subjects who do not usually consume foods siad "reduced in sugars" or "light"
• Subjects who do not consume regularly pre- and probiotics in the form of dietary supplements

Exclusion Criteria:

• subjects presenting Irritable bowel syndrome
• history of chronic GI disorders: crohn disease, ulcerative colitis,....
• treatments likely to influence GI sensitivity or motility (laxative, neuroleptics,...)
• Antibiotic therapy in progress or in the past 8 weeks
• medical history with impact on the study objectives as defined by investigator
• known food allergy to one of the compounds of the study product

Identical sachets containing 5g of scFOS or placebo (maltodextrins)