The bees use the propolis in order to close both the openings and entrance of the nest, therefore avoiding the cold air stream during winter and the action of predators. Because their bactericidal and fungicidal properties, the propolis is also used to clean the colony as well as to isolate a part of the nest or some strange body that cannot be removed from the colony. Its composition, color, odor and medicinal properties rather depend on the species of plant available to bees. Nowadays, the propolis is mainly used by the cosmetics and pharmaceutical industries.