Iceland lichen – in addition to having a number of medicinal properties, Iceland lichen is a very important indicator of clean air because it survives only in a clean environment. Iceland moss is most commonly used in upper respiratory tract irritations, and the main active ingredients are polysaccharides-lichenins and isolihenins. Polysaccharides coat irritated and damaged mucous membranes, and lichenins also have an anti-inflammatory effect on the mucous membranes and reduce the stimulus to cough. An important component of Iceland lichen is also usic acid, which acts as a natural antibiotic. Due to these beneficial effects, Iceland moss preparations are used in the treatment of various types of colds, dry irritating inflammations of the oral cavity and pharynx, and in bronchial catarrh and cough. Iceland lichen liquid dietary supplement is taken three times a day, depending on age, in an amount of 5 to 15 ml. It can be taken by children older than 1 year.