Background: The hippocampus plays a major role in memory. Aluminium chloride (AlCl₃) is an Alzheimerogenic compound. Stem cells are promising. The work aimed to evaluate the stem cells in ameliorating the hippocampal changes induced by AlCl₃. Material and methods: 24 adult male albino rats, aged two months, weighing 200-250 gm were randomly divided into group A (control group) that was divided into group A1 (6 rats) received no treatment and group A2 (6 rats) received 1 ml of normal saline intraperitoneally once daily for 60 days, group B (AlCl₃-treated group) consisted of 6 rats and received 40 mg AlCl₃/kg b.w. intraperitoneally once daily for 60 days, and group C (AlCl₃+ MSCs-treated group) consisted of 6 rats and received 40 mg AlCl₃/kg b.w. intraperitoneally once daily for 60 days then received an intraperitoneal injection of one million bone marrow mesenchymal stem cells (BM-MSCs) and kept for 3 weeks without treatment. At the designated time, all rats were anaesthetized, sacrificed and the brains were extracted and processed for histological, immunohistochemical, and morphometric studies. Results: The hippocampus of group B showed apoptotic cells, vacuolated cytoplasm, eosinophilic patches, neurofibrillary tangles, and dilated congested blood vessels as well as statistically significant decreases in the granular layer and stratum pyramidale thickness, diameter of pyramidal cells' nuclei, and number of pyramidal cells, and an increase of the area % of GFAP, caspase-3 and ubiquitin immunoreactivity. Group C showed a noticeable regression of these changes. Conclusion: AlCl₃ has an injurious impact on the hippocampus. It could be alleviated by BM-MSCs.