The current review of the in situ gelling system is one of the most popular and prominent. Shipping has huge benefits system due to many advantages such as using simple manufacturing; improve patient compliance and comfort by reducing frequency. The drug has a unique property of moving the left gel. Also, in situ gelling nanoemulsions provide nanosphere, microspheres and liposomes. Disadvantages associated with conventional solution and gel systems include accurate and easy dosing administration is overcome by using the in situ gelling system. This overview covers definitions, types, advantages, disadvantages, polymers used and favorable properties of polymers by preparing in situ gels coated on the substrate. Approach, application and evaluation. Gels in situ are explained with examples.