Polymeric biomaterials are widely used as carriers for cells and therapeutic agents. Until recently, most research has been limited to a relatively narrow number of monomers and chemistries. A fundamental challenge in developing clinically relevant polymeric biomaterials is to independently control their chemical and physical properties across multiple scales in both time and space. Control over a biomaterial's chemical and physical properties is critical to recapitulate the complex cascades of signals and complex microenvironments found in nature. Typically, dynamically responsive biomaterials either degrade in the presence of a stimulus (i.e., water induces hydrolysis) or experience a change in solubility on application of the stimulus (i.e., temperature induces gelation via lower critical solution temperature LCST). This highlight discusses recent advances in stimulated and controlled degradation of polymeric biomaterials. The goal of this review is to provide a broad overview of physiologically relevant stimuli used to control the degradation of a wide range of polymeric biomaterials with varying architectures and physical forms. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3531-3566