Propolis is sometimes otherwise known as 'bee glue'. Its a sticky resinous mixture that honey bees produce by mixing salvia and bees wax with tree resin. It's most commonly known use is it to seal unwanted gaps in their nest cavities and create a sterile environment to help maintain the health of the colony. It is made up of many antibacterial, antiviral, antifungal and anti inflammatory properties with the likes of the Ancient Egyptians, Greeks and Romans using it to reduce wound infections and speed up healing. More recent applications of bee propolis now encompases the likes of skin care and immune support products.
Beekeepers are also realising its importance in nest cavities. Experiments on colonies kept in brood boxes either with or without propolis painted on the internal walls have found that the levels of infection of both American Foul Brood and Chalkbrood (2 well known bee diseases amongst beekeepers) were significantly reduced in the painted propolis boxes.