Ruellia tuberosa Linn. of family Acanthaceae was studied to investigate the microscopical, vein islet and vein termination numbers, palisade ratio, stomatal index and different chemical parameters. The antibacterial, antifungal and phytotoxic activities of the crude extract of the plant were also determined. Five bacterial species were used, of which, Salmonella typhi, Escherichia coli, and Pseudomonas aeruginosa were the most susceptible bacterial species to crude extract with MICs 10, 4.0 and 14mg/ml, respectively. Among the tested fungal species Fusarium solani and Aspergillus niger were more susceptible to crude extracts with MICs 1.34, 2.78 and 1.45μg/ml, respectively. At the concentration of 1000μg/ml the methnolic extract exhibited significant activity, at 100μg/ml the activity was good and at 10μg/ml the activity was moderate against Lemna minor. The above selected plants were shown by in vitro assays to be a potential source for natural antifungal, antibacterial and phytotoxic agents.