The antimicrobial activity of the total alkaloids from the leaves of Mitragyna inermis (Willd.) O. Kuntze (Rubiaceae) From Burkina Faso was evaluated using disc diffusion essay and broth microdilution assay. The extract was used against ten (10) reference bacterial strains and three (3) clinical isolates including Gram(+) and Gram(-) strains. The alkaloids showed moderate activity against mcroorganisms tested. The highest Diameter of Inhibition Zone (DIZ) was obtained with S. aureus ATCC9244 (23 ± 1 mm). The lowest Minimum Inhibitory Concentration (MIC) obtained was 0.625 mg mL-1 recorded with three (3) Gram(+) bacteria (S. aureus ATCC 25293, S. aureus (clinical isolate) and S. carmorum LMG 13567) and one Gram(-) strain (P. mirabilis CIP104588. Results showed that Gram(+) bacteria are more sensitive to alkaloids from M. inermis than Gram(-) bacteria. This study confirmed the use of the plant in traditional medicine against some infectious diseases.