In intestinal diseases, to calm bleeding, against hyperthyroidism. Due to its iodine content, it is used for bronchitis, cough, intestinal diseases, and hyperthyroidism. The XVII. s. since the Icelandic lichen has been one of the most popular remedies in folk medicine for lung and throat complaints. Due to the large amount of plant mucus, its active ingredient is bitter lichen acid, which is also attributed an antibiotic effect. Official medicine recommends it to relieve the cough stimulus in upper respiratory diseases, but regardless of this, it is also recommended for any cold or infectious disease due to its antiseptic effect.