This handbook contains a succinct overview of the medicinal plants that are most commonly used in Indian systems of medicine. There are nearly 200 plant species belonging to 72 families that are either used as primary sources of drugs or as substitutes for drugs. The medicinal plants have been classified according to Bentham and Hooker’s system of classification, with each family being assigned a number. In tabular format, the following basic information about drug plants is provided: names (Botanical and Tamil), habits of the plants, part (s) used in medicine, main properties/uses, and the general name of the area (s) where the plants naturally occur. In addition, the names of commonly encountered and important drug plants have been provided. There are also indexes of botanical names, Tamil names, and clear images available.