Propolis is a resinous mixture produced by bees - usually a combination of beeswax, saliva and resin from nearby plants. Worker bees use propolis to seal up small gaps in their beehives - current research suggests this may make the hives more structurally sound as well as more resilient to predators and disease. Propolis has natural antimicrobial and anti-inflammatory properties, and can be used in toothpastes to help protect the gums and teeth.