Propolis, also known as bee putty, is a solid, resinous substance consisting of various natural components. The name comes from the Greek ("pro" = for, "polis" = city) and means "for the state" - a reference to its important function for the bee colony.

Bees use propolis in many ways: it is used as a building material for insulation and to repair the hive. At the same time, it has a protective effect by sealing the hive against moisture and draughts and also forms a barrier against bacteria and other microorganisms.