Mucilage is a gelatinous substance, produced by almost all plants and some microorganisms, which contains proteins and polysaccharides and is similar to plant gums. It is involved in water and food retention, membranes thickening and seed germination. Flax seeds and cacti as well as other succulents are rich sources of mucilage, which is edible and used in medicine to relive mucos membrane irritation by forming a special protective film.