This Handbook contains the brief information on medicinal plants mainly used in Indian Systems of Medicine. Nearly 1000 plant species belonging to 164 families either used as main sources of the drugs or as their substitutes and adulterants are given in it. The drug plants have been given familywise following the Bentham and Hooker's system of classification. The brief information about the drug plants i.e. Names (Sanskrit & Botanical) habit of the plants, part(s) used in medicine, main properties/uses and broadly the name of area(s) where the plants naturally occur has been given in tabular form. The names of common substitutes and adulterants of important drug plants have also been provided. Indexes of botanical and Sanskrit names have also been given at the end. The book has been written in a very easy and simple manner, so that an average reader can follow it. The specific features of this small reference book are: (a) The information, including the names of substitutes and adulterants are given in tabular form, so that one can see it at a glance. (b) The book can be kept easily is hand in field and other places. (c) Important medicinal plants of the families have been indicated. (d) The book contains nearly all those plants which are prescribed in various courses of Ayurveda, pharmacy, Medico-botany etc. The book is useful to the students, teachers, researchers on medicinal plants, herbal based pharmaceutical concerned, N.G.O's and other those who are interested in medicinal plants.