Essential oils isolated from six Philippine plant species, namely Alpinia brevilabris C. Presl, Alpinia cumingii K. Schum., Alpinia elegans (C. Presl) K. Schum., Callicarpa micrantha Vidal, Cinnamomum mercadoi S. Vidal, and Piper quinqueangulatum Miq. were assessed for their in vitro growth-inhibitory effect against pneumonia causing bacteria (Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus) using the broth microdilution volatilization method. Additionally, a modified thiazolyl blue tetrazolium bromide assay was performed for evaluation of their cytotoxic activity to human lung cells. All essential oils exhibited some antibacterial efficacy in liquid phase; however, only A. cumingii oil was active in the vapour as well. Both A. cumingii and A. elegans oils showed the most effective antibacterial potential against H. influenzae in liquid medium with the minimum inhibitory concentration of 256 µg/mL. Using dual-column/dual-detector system GC/MS analysis, hedycaryol, β-pinene, caryophyllene epoxide, aristolochene, borneol, and linalool were identified as the major components of A. brevilabris, A. cumingii, A. elegans, C. micrantha, C. mercadoi, and P. quinqueangulatum leaves oils, respectively.