This book deals about medicinal plant especially on Rauvolfia, classification of ¿-Glucosidase and industrial application of ¿-glucosidase, natural component of Ravolfia and its applications, secondary metabolites from plants, role of beta- glucosidase in development and growth of the plant, plant secondary metabolism, as built in defense control system, degradation of biomass, manipulation of lignin biosynthesis and paper quality, structure and substrate specificity of ¿-glucosidase, the mechanism of catalysis, purification and characterization and industrial application. It elaborate the method of alkaloid extraction, TLC analysis, ¿-Glucosidase assay, protein estimation, electrophoresis, purification of ¿-glucosidase, dialysis, Sephadex G-25 column chromatography, lyophilization, characterization of enzyme, molecular weight estimation, determination of pH optimum, temperature, thermal stability, effect of varying concentration of the substrate, ions, metabolites, active site modifiers and chelators on the activity of ¿-glucosidase and statistical analysis and formula used for calculation of analysis of variance stepwise.