Propolis is a resinous substance collected by bees from tree buds and used to seal their hive. It has been used for centuries as a medicine due to its antimicrobial and anti-inflammatory properties. The document reviews the history of propolis use from ancient Egypt and Greece to modern times. It discusses the typical composition of propolis which varies depending on its botanical source, and summarizes over 300 studies showing propolis has antioxidant, anticancer, antiviral, antibacterial and other health benefits when tested on cells and animals. The main functional effects include antimicrobial, antiviral, antifungal, anti-ulcer, hepatoprotective, antitumor and anti-inflammatory properties.