Although the significance of burst release in controlled delivery systems has not been entirely ignored, no successful theories have been put forth to fully describe the phenomenon. Despite the fact that the fast release of drug in a burst stage is utilized in certain drug administration strategies, the negative effects brought about by burst can be pharmacologically dangerous and economically inefficient. Therefore a thorough understanding of the burst effect in controlled release systems is undoubtedly necessary. In this article, we review experimental observations of burst release in monolithic polymer controlled drug delivery systems, theories of the physical mechanisms causing burst, some of the unique ideas used to prevent burst, and the treatment of burst release in controlled release models.