Evaluation of the in vitro antibacterial activity of Methanol extracts isolated from Henna (Lawsonia inermis) leaf against two food born infection causing pathogens, gram-positive Staphylococcus aureus and gram-negative Klebsiella pneumoniae. This interventional study was carried out in the Department of Pharmacology and Therapeutics in collaboration with the Department of Microbiology, Mymensingh Medical College, Bangladesh from January 2021 to December 2021. The antibacterial activity was tested at different concentrations of Methanol Henna leaf extracts by using disc diffusion and broth dilution method. The extract was prepared by using solvents Methanol and 0.1% dimethyl sulfoxide (DMSO). The test microorganisms were also tested for their activity against a standard antibiotic Ciprofloxacin by broth dilution method and the result was compared with that of Methanol extracts. Methanol Henna Extracts (MHE) were used initially in nine different concentrations (2.5, 5, 10, 20, 50, 100, 200, 500 and 1000mg/ml) and later in selected concentrations as needed to confirm the more precise margin of antimicrobial sensitivity of the extracts. Among different concentrations of the MHE, 100mg/ml and above concentrations showed inhibitory effect against afore said bacteria. The MIC for Staphylococcus aureus and Klebsiella pneumoniae were 100mg/ml in MHE. The MIC of Ciprofloxacin was 1μg/ml against Staphylococcus aureus and 1.5μg/ml for Klebsiella pneumoniae. The MIC of Ciprofloxacin was the lowest in comparison to MICs of MHE for the test organisms. This study showed that Methanol Henna extracts demonstrated antibacterial effects against pathogens. From this study, it is clearly observed that there is definite antibacterial effect of the methanolic extract of Henna leaves (Lawsonia inermis) against Staphylococcus aureus and Klebsiella pneumoniae.