NOW® Raw Bee Propolis is collected from beehives and has naturally occurring flavonoids. Bees collect the propolis from the resin of certain select trees and use it to line the hive. This substance is believed to be responsible for the sterile, healthy state of the beehive colony. The name "propolis" is derived from the Greek words "pro" which means "before" and "polis" which means "city". This refers to its use at the "door" of the bees city of wax.