The crude ethanolic extract of leaves(ZLE) and fruits (ZFE) of Zanthoxylum armatum were scrutinized for acute toxicity and antipyretic activities while crude ethanolic and n-hexane extract of the leaves (ZLE, ZLH) and fruits (ZLE, ZLH) of this plant were screened out for their phytotoxic and cytotoxic potential. The extract were found to be safe at a dose of 500, 1000 and 2000 mg/kg body weight. The antipyretic activity of leaves and fruits were tested on mice using Brewer's yeast induced pyrexia model, both the extract, that is, ZLE and ZFE were found to active in lowering pyrexia in the tested animals. The antipyretic effect of fruits was more significant than leaves. ZFE showed a percent inhibition of 83.84, 80.70 and 44.18 at the dose of 300, 200 and 100 mg/kg, respectively at the 3rd hour while ZLE showed a percent inhibition of 85.42, 77.19 and 46.18 respectively at the dose of 300, 200 and 100 mg/kg, respectively. The antipyretic action was observed to be maximum at the 3rd hour of the dose, which remain significant up to 5th hour. The ZLE, ZLH, ZFE and ZFH also showed significant potency as phytotoxic and cytotoxic agent. Phytotoxicity and cytotoxicity were found to be dose dependant and showed maximum efficiency at 1000 mu g/ml. It is concluded that Z. armatum a potential antipyretic, phytotoxic and cytotoxic medicinal plant. Further investigations are required to identify and isolate its active principals responsible for its pharmacological activities.