The work embodied in my book is mainly concerned with the isolation and characterization of chemical constituents from three terrestrial plants. The isolated compounds, whether new or which have been previously reported in the literature, were characterized by using various sophisticated spectroscopic techniques available at this institution. The present book describes the isolation of five new compounds including triterpenoidal saponin and pterocarpans from Zygophyllum eurypterum Boiss and Buhse (syn. Z. atriplicoides Fisch. and Mey). The new compounds isolated were named as Atriplicosaponin A (1), Atricarpan A (2), Atricarpan B (3), Atricarpan C (4) and Atricarpan D (5). Three known compounds were isolated from Zygophyllum simplex Linn. named as Ursolic acid (6), ?- Sitosterol (7) and Oleanolic acid (8). These known compounds alongwith ?-Sitosterol glucoside (9), Guaianin M (10) and Guaianin N (11) were also isolated from Guaiacum officinale Linn.