Aim: Medicinal plants have been globally used as alternative to synthetic drugs in treating different disease conditions. This study investigated the effect of oral administration of ethanol leaf extract of Justicia insularis in Phenylhydrazin induced anaemia in Wistar rats. Methods: A total of 30 male Wistar rats including 24 anaemic and 6 normal rats were used for experiment. Anaemia was induced in rats by intraperitoneal administration of phenylhydrazine at a dose of 40 mg/kg for 48 hours. After being confirmed anaemic, rats were orally treated with distilled water and ethanol extract of Justicia insularis at doses of 200 mg/kg, 400 mg/kg and 600 mg/kg respectively for three weeks. The haematological parameters including the red blood and white blood cells and their functional indices were investigated in anaemic treated rats compared with the control rats. Phytochemical analysis and acute toxicity test of the extract were also carried out. Results: Administration of the ethanol leaf extract of J. insularis daily for three weeks significantly increased the haematological parameters which conclude that it exhibits antianaemic activity. Phytochemical test on J. insularis indicated the presence of alkaloid, saponins, tannins, flavonoids, terpenoids, steroids, glycosides, phenol, resins and reducing sugar. The extract was also found to be non-toxic in rats. Conclusion: The implication of our findings is that ethanol leaf extract of J. insularis possesses potent antianaemic activity and thus, could be considered a potential candidate for the development of new drug in the treatment of anaemic conditions.