The objectives of this study were analysis of the secondary metabolite products and evaluation antibacterial activity. Bioactives are chemical compounds often referred to as secondary metabolites. Twenty one bioactive compounds were identified in the methanolic extract of Saccharomyces cerevisiae. The identification of bioactive chemical compounds is based on the peak area, retention time molecular weight and molecular formula. GC-MS analysis of Saccharomyces cerevisiae revealed the existence of the Thieno [2,3-c] furan-3-carbonitrile, 2-amino-4,6-dihydro-4,4,6,6-, Oxime-, methoxy-phenyl-,Acetic acid, N -[3-(1-hydroxy-1-phenylethyl)phenyl] hydrazide, 1-Aminononadecane, N-trifluoroacetyl, Androstane-11,17-dione,3- [(trimethylsilyl)oxy]-,17-[O-(phenylme, Benzeneacetamide,?-ethyl-, 4-Benzyloxy-6-hydroxymethyl-tetrahydropyran-2,3,5-triol, 1,2-Ethanediol, 1-(2-phenyl-1,3,2-dioxaborolan-4-yl)-,[S-(R*,R*)], Erythritol, 3,6,9,12,-Tetraoxatetradecan-1-ol,14- [4-(1,1,3,3- tetramethylbutyl, Urea,N,N -bis(2-hydroxyethyl)-, Ergosta-5,22-dien-3-ol,acetate,(3?,22E)-, Ethyl iso-allocholate, (5?)Pregnane-3,20?-diol,14?,18?-[4-methyl-3-oxo-(1-oxa-4-azal,5,5 -Dimethoxy-3,3 ,7,7 -tetramethyl-2,2 -binaphthalene-1,1 ,4,4 ,N-(4,6-Dimethyl2pyrimidinyl)-4-(4 nitrobenzylideneamino) benzene, 3-[3-Bromophenyl]-7-chloro-3,4-dihydro-10-hydroxy-1,9 (2H,10H), 2-Methyl-9-?-d-ribofuranosylhypoxanthine, Dodecane,1-chloro-, 2,7-Diphenyl-1,6-dioxopyridazino [4,5:2 ,3 ] pyrrolo [4 ,5 -d] pyridazin and 2-Bromotetradecanoic acid. Evernia punastri was very highly antifungal activity (7.00±0.25) mm. The results of anti-bacterial activity produced by Saccharomyces cerevisiae showed that the volatile compounds were highly effective to suppress the growth of Proteus mirabilis.