Drug design, often apply to as rational drug design or simply rational design, is the inventive process of finding new medications based on the knowledge of a biological target. The drug is most generally an organic small molecule that activates or inhibits the function of a biomolecule such as a protein, which in turn results in a therapeutic benefit to the patient. In the most basic sense, drug design affect the design of molecules that are complementary in shape and charge to the biomolecular target with which they interact and therefore will bind to it. Drug design frequently but not necessarily relies on computer modeling approaches.This type of modeling is sometimes referred to as computer-aided drug design