ABSTRAKTelah dilakukan uji aktivitas antibakteri Eschericia coli (E. coli) minyak batang genoak (Acorus calamus). Penelitian ini dilakukan melalui destilasi uap batang genoak yang diikuti analisis komposisi kimianya menggunakan GC-MS, dan uji antibakteri terhadap bakteri E. coli menggunakan metode hitung cawan. Hasil penelitian diperoleh minyak genoak dengan rendemen 0,17% dan asaron sebagai komponen utama minyak genoak sebesar 89,81%. Minyak genoak dapat menghambat pertumbuhan bakteri E. coli sebesar 95,76% pada kosentrasi 10% (v/v).Kata kunci : Destilasi uap, Batang Genoak (Acorus calamus), E. coli, Asaron. THE ANTI Eschericia coli STUDY OF GENOAK(Acorus calamus) OIL FROM TIMOR ABSTRACTThe study of anti Eschericia coli (E. coli) of genoak oil (Acorus calamus) has been done. The research aimed to emerge the potential characteristic of genoak oil which distilled from its stem part. The anti bacterial study was done using plate count method, whilist the chemical compound contained in the oil was investigated using GC-MS. The research result show that asaron in the major compound in stem part of genoak i.e. 89.81%. The genoak oil inhibited 95.76% of the E. coli growth at 10% (v/v) of its concentration.