Environmental responsive nanocarriers are nanostructures which are capable of bringing chemical and physical modifications for receiving internal or external stimuli. This chapter discusses the most significant progress in developing environment-responsive polysaccharide nanocarrier drug delivery systems in response to specific stimuli both endogenous and exogenous. Polysaccharides are one of the most popular polymeric materials for stimuli-responsive drug delivery systems. Natural polysaccharides have received more attention in the new era of environmental responsive drug delivery. The chapter also discusses the different polysaccharides modulated with stimuli sensitivity. Alginate is useful in the design of controlled delivery systems because of its pH-sensitivity, bioadhesiveness, biocompatibility, and mild gelation conditions. In an oral delivery system, alginate beads have been used for the controlled release of macromolecules in a low pH solution. The design and development of environment-responsive smart biopolymers are increasing in the application of drug delivery.