Anggraini, Dini2021-08-262021-08-262020-11wahyu sari yenihttps://repository.unri.ac.id/handle/123456789/10172Disease due to infection is one of the growing problems in the health sector. Infection caused by pathogenic bacteria can cause various diseases such as diarrhea. Diarrhea can be caused by Escherichia coli, Salmonella typhimurium and Shigella flexineri. Actinomycetes are one of the antibiotic producers. The actinomycetes used were isolated from the soil of the Universitas Riau Arboretum with isolate codes A2.01, B1.06, B3.12, C2.18 and C2.20. The purpose of this study was to determine the antibacterial ability of the secondary metabolites of actinomycetes extracted using warm methanol solvent (40oC) against pathogenic bacteria causing diarrhea. Antibacterial activity test was performed using the disc diffusion method. The results of the antibacterial activity test showed that actinomycetes isolates were able to inhibit diarrhea-causing bacteria, with an inhibition zone of 15.7 mm by isolate B3.13 against Escherichia coli, 10.6 mm by isolate C2.18 against Shigella flexineri, and 12,8 mm by isolate B3.13 against Salmonella typhimurium. The inhibition zone criteria so that the activity of the secondary metabolites of actinomycetes can be categorized into weak, moderate and strong.enActinomycetesantibiotic,warm methanolsecondary metabolitesextractionArticle