Stenochlaena palustris (local name: Kalakai) is an edible ferns, that found in the tropical and subtropical forest. It known by the people as a highly nutritious vegetable. This study was conducted to determine the chemical compounds from ethanol extract of Kalakai using gas chromatography-mass spectrometry (GC-MS) technique and antibacterial activity against Staphylococcus aureus dan Eschrichia coli. Interpretation of GC-MS spectrum showed four chemical compounds. Stigmasterol and its derivatives are the major compounds (total 97.47%) and ethyl linoleate is a minor compound (2.57%). Stigmasterol has various interesting bioactivity based on a literature review. While the value of minimum inhibition concentration (MIC) of ethanol extract of Kalakai is 10% (w/v) against both Staphylococcus aureus and Eschrichia coli.