This study carried out on the methanol extract from the bark of the Manilkara mabokeensis plant, in order to determine the active principle and its effect on the strains of Staphylococus aureus, Shigella sp and Escherichia coli. Two methods of antibiogram (dilution and diffiusion) were used. The methanol of diffusion in solid medium (Mueller Hinton), induced growth inhibition diameter of 20mm, on E. coli and Shigella sp, respectively. However, the S. aureus brain multiplied around the plant extract disc. For the dilution method, the minimum inhibitory concentration was 0.07 for E. coli and 0.09 for Shigella sp. Therefore the extract of the plant was found to be active with a bactericidal effect for E. coli and bacteriostatic effect for Shigella sp. Chemical screening revealed the presence of tannins, flavonoids, the power and quinones. These results confirm the use of this plant to treat some cases of infections observed in the traditional workplace.