Provided herein are chitosan-containing formulations, methods of making such formulations, and methods of using such formulations. Chitosan contemplated for use herein is preferably of high quality and its source is preferably of crustacean origin. The formulations contemplated herein are aqueous, either liquid- or viscous-like, varying in concentration and type of chitosan and acid used, and may include other components. Their uses are diverse, for oral/dental administration or topical/surface application to subjects (e.g. humans or animals) in need thereof or even food commodities, aiming to maintain a good condition where it is applied or contributing to health enhancement, healing, disease prevention or treatment. The present invention also relates to concentrated solutions that may be used for the formulation of other products.