Background: In Niger as in other developing countries, the diarrheal diseases constitute a serious problem of public health. To treat diarrhea, most Niger people living in the rural areas do rely on medicinal plants. To evaluate the traditional use of these plants, scientific validation is needed. Objectives: The plant species studied here are traditionally used in Niger to treat diarrhea. The aim of this study was to investigate the antibacterial activities of these plants against enteropathogenic bacteria isolated from clinical stool samples. Materials and Methods: The collected plant materials were dried, pulverized, and methanol extracts were prepared. The total and serially diluted fractions of the extracts were assayed for antibacterial activities against selected enteropathogens by agar well diffusion and deep-well microdilution methods. Results: The extracts of Acacia nilotica, Sclerocarya birrea and Combretum nigricans exhibited the highest antibacterial activities against Escherichia coli (21.9 ± 0.6 mm zone of inhibition and minimum inhibitory concentration [MIC] 0.9 mg/mL), Salmonella typhi (19.6 ± 0.2 mm zone of inhibition and MIC 0.9 mg/mL) and Shigella flexneri (18 ± 0.6 mm zone of inhibition and MIC 3.7 mg/mL), respectively. Conclusion: The results of this study provided some insight into the antibacterial activities of the plants traditionally used by the people of Niger republic to treat diarrhea.