Abstract: Three terpenes lup-20 (29)-en-3-one (ZB-1), 11 , 13-dihydro-1epireynosin (ZB-2) and tetracyclic diterpenol-15-cinnamate (ZB-3) were isolated from the bark of the plant Zanthoxylum budrunga and were screened against some pathogenic bacteria and fungi. They were found significant in vitro antibacterial and antifungal. The zones of inhibition produced by the pure compounds were laid between 9 mm to 23 mm. The MIC values of the three isolated compounds were also determined against four test organisms (107 cells/ml) and were found to be effective between 16 μg/ml to 128 μg/ml.