A food can be regarded as functional if it is satisfactorily demonstrated to affect beneficially one or more target functions in the body, beyond adequate nutritional effects, in a way which is relevant to either the state of well-being and health or the reduction of the risk of a disease. Health claims are expected to be authorized for functional foods based either on enhanced function (type A claim) or disease risk reduction (type B claim). Their development is a unique opportunity to contribute to the improvement of the quality of the food offered to consumer's choice for the benefit of his well-being and health. But only a rigorous scientific approach producing sound data will guarantee its success. The functional food components that are discussed in the proceedings of the 3rd ORAFTI Research Conference are the inulin-type fructans, natural food components found in miscellaneous edible plants. They are non-digestible oligosaccharides that are classified as dietary fiber. The targets for their functional effects are the colonic microflora that use them as selective 'fertilizers'; the gastrointestinal physiology; the immune functions; the bioavailability of minerals; and the metabolism of lipids. Potential health benefits may also concern reduction of the risk of some diseases like intestinal infections, constipation, non-insulin dependent diabetes, obesity, osteoporosis or colon cancer. The present proceedings review the scientific data available and, by reference to the concepts in functional food science, they assess the scientific evidence which will be used to substantiate health claims.