Over the past ten years, in-situ gelling drug delivery devices have attracted a lot of attention. They are in a sol state prior to delivery, and they get converted to gel when exposed to a wide range of physical stimuli, including changes in temperature, pH, and the presence of ions. One of the natural polymers employed frequently in protein and drug delivery systems is alginate. Oral administration of liquid dosage forms with in situ gelling properties may be beneficial for elderly patients who have difficulty swallowing. Numerous uses for sodium alginate have prompted researchers to concentrate on developing novel in-situ gelling systems. Oral sustained release drug delivery has several advantages over other dosage forms, such as simpler dose administration, increased patient compliance, formulation flexibility, and cost effectiveness, and is therefore receiving more and more attention in the pharmaceutical industry. The chemistry of sodium alginate, the rationale for using alginate as a carrier for oral in-situ gelling systems, the principle of in situ gel formation, the method for preparation of oral Gastroretentive in-situ gel, and a literature survey on alginate-based oral in-situ therapy for various therapeutic agents have been discussed in this paper. This article provides a comprehensive review of alginate's current status and advancement in the sol-to-gel transition phase. The future of alginate polymer applications in pharmaceutical and biomedical research is bright. Alginate's safety, biocompatibility, and ease of preparation are some of its most significant features. The demand for the development of liquid oral controlled-release drug delivery systems increased due to the expected improvement in patient compliance and flexibility of dosing. Overcoming the potential for dose dumping was necessary for the area's advancement. This prompted researchers to use a variety of gastro-retentive techniques to prevent dose dumping once the rigid gel structure in the intestinal environment was destroyed. As a result, researchers must update the developments in alginate-based drug delivery systems, and this review provides advice for future study. Key words: In-situ gelling systems, Drug Delivery, Sodium Alginate, pH induced ion gelation, sol to gel transition.