Essential oils (EOs) of Salvia fruticosa Mill. gathered from three Palestinian localities were studied to determine their constituents, antibacterial adhesion impact against Klebsiella pneumonia, cytotoxicity, and their function in cancer cell migration. Gas chromatography-mass spectrometry identified the chemical components, while the MTT technique was used to measure the EOs' cytotoxicity against HeLa (cervical) and Caco-2 (colorectal) cancer cells. Antibacterial adhesion was assessed by examining Klebsiella pneumoniae's ability to adhere to Caco-2 cells. Our study found that eucalyptol was present as the main constituent in all S. fruticosa EOs. In addition, K. pneumoniae adhesion and metastasis were reduced after 48 h of application. Salfit's and Hebron’s EOs had the most potent cytotoxic effects on Caco-2 and HeLa, with IC50 values in the range of 0.7–1.3 μg/mL. Using S. fruticosa EOs as a disinfectant to treat and prevent illnesses caused by K. pneumoniae and to treat cancer may be possible.