Background: The aqueous decoction of the stem back of Mangifera indica L. has been traditionally used for the treatment of various illnesses among them includes anaemia. Aims: The aim of this study was to investigate the anti-anaemic properties of standardized stem bark extract of M. indica in animals with 2,4-dinitrophenylhydrazine-induced haemolytic anaemia. Methods and Material: An in vivo animal model was used in this experiment. 2,4-dinitrophenylhydrazine was used to induce haemolysis and treatment was done with three different concentrations (25, 50, and 100 mg/kg b.wt) of the plant extract. Astifer® was used as a positive control. Haematological parameters such as PCV, HGb concentration, and TLC were performed and to ascertain the level of haemolysis. GC-MS was used determine the present of phytoconstituents within the crude extract. Results: PCV and HGb concentration increased significantly (p<0.001) at a dose of 50 and 100 mg/kg b.wt respectively while no significant (p>0.05) effect was observed at a dose of 25 mg/kg b.wt. TLC was decreased significantly (p<0.001) at a dose 100 mg/kg b.wt while no significant (p>0.05) effect was observed at a dose of 25 and 50 mg/kg b.wt respectively. GC-MS analysis revealed presence of 15 compounds viz: 2,2-Dimethoxybutane, N-Acetyl-Alpha-D-glucosamine, 1,2-Benzenediol, Phenol, 2,4-bis(1,1-dimethylethyl)-, Vitamin E, Pentadecanoic acid, 13-methyl-, methyl ester, 2-Ethylacridine, Benzofuran-6-ol-3-one, 2-(4ethoxycarbonyl)benzylidene-, 9-Octadecanoic acid, (E)-, 2,4,6-Cycloheptatrien-1-one, 3,5-bis-trimethylsilyl-, and Benzo[h]quinoline,2,4-dimethyl-. Conclusion: The results of our present finding suggest the significant anti-anaemic properties of standardized stem bark extract of Mangefera indica L. This finding highlights the potentials of the extract and M. indica in the treatment of haemolytic anaemia.