The oral delivery of drugs with a narrow absorption window in the gastrointestinal tract (GIT) is often limited by poor bioavailability with conventional dosage forms due to incomplete drug release and short residence time at the site of absorption. To overcome this drawback and to maximize the oral absorption of these drugs, novel drug delivery systems have been developed. Gastroretentive systems such as floating systems, mucoadhesive, high-density, expandable and have been developed, since they provide controlled delivery of drugs with prolonged gastric residence time. Among all oral dosage forms, liquid orals are more prone to low bioavailability as far as stomach specific drug deliveries are concerned, since they subjected to faster transit from the stomach/ duodenum. To produce sustained release formulation of an oral liquid formulation could be successfully augmented substantially through a strategy of liquid in-situ floating gel system. The formation of gel depends on factors like temperature modulation, pH change, presence of ions and ultra violet irradiation, from which the drug gets released in a sustained and controlled manner. This comprehensive article contains approaches, polymers, marketed preparations, patents, herbal approaches and recent advances of in situ gel.