721-733Despite considerable progress in medicinal chemistry in the last century, rational drug design that allows the development of effective pharmaceutical agents with minimal side effects is still an elusive goal. The primary causes for side effects are the generalized effect of drug on receptors present throughout the body and uncontrolled drug metabolism. Thus, it has become evident that targeting and metabolism considerations should be an integral part of any drug design process and that the focus should be on increasing activity as well as therapeutic index of the potential drug candidate. Various ideas have been suggested over the years to come up with an ideal approach to drug design. In this review, we shall be dealing with one such approach, that is, the soft drug approach. A soft drug is pharmacologically active as such, and it undergoes a predictable and controllable metabolism to nontoxic and inactive metabolites. The main concept of soft drug design is to avoid oxidative metabolism as much as possible and to use hydrolytic enzymes to achieve predictable and controllable drug metabolism. The discussion shall present an overview on the need for the development of soft drugs, associated terminologies and the different classes of soft drugs