The role and importance of a soluble fraction of dietary fibre, especially of β-glucans contained in oat grains, decidedly increased after their properties have become known. The thoroughly and well documented research focused on the structure, physical, chemical & nutritional properties of those compounds caused oats to have regained recognition and to have become a valuable dietary component. The most important health promoting properties of oats (mostly owing to the presence of β-glucans) are the following: capacity to decrease cholesterol level and to support obesity treatment, participation in treating inflammatory state of intestines and stomach mucosa, capacity to alleviate chronic peptic ulcer disease effects, power to increase immunity and well being, especially of people of advanced age. There are also some reports on possibilities of applying β-glucans to treat tumour and diabetes, or to accelerate wound healing and to alleviate inflammatory states of skin. Those important properties of oats caused manufacturers to begin to add oat fibre preparations to some food products; in this way, those food products gained the name and status of functional food. Most frequently, oat fibres are added to cereal products. Milk and meat products also contain oat fibres. In some cases oat fibres can lower sensory values of the final product, and in those cases it is possible to add β-glucans in the form of oat maltodextrin with a low conversion factor, and to utilize other properties of maltodextrin (for example, it is an excellent fat replacer). Before β-glucans are applied to food products, the impact of technological factors on the pro-health and rheological properties of β-glucans must be well studied and analysed.