Polysaccharide depolymerase, a polysaccharide hydrolase encoded by bacteriophages (or ‘phages'), can specifically degrade the macromolecule carbohydrates of the host bacterial envelope. This enzyme assists the bacteriophage in adsorbing, invading, and disintegrating the host bacteria. Polysaccharide depolymerase activity continues even within biofilms. This effectiveness means phages are promising candidates for novel antibiotic scaffolds. A comprehensive compendium of bacteriophage polysaccharide depolymerases has been compiled, together with their potential biomedical applications, such as novel antibiotics, adjuvants for antibiotics, bacterial biofilm disruptants, and diagnostic kits.