Objectives: To investigate antimicrobial and cytotoxic potentials as well as chemical constituents of extracts from Macaranga barteri(M. barteri).Methods: Antimicrobial activity was carried out using micro-dilution, cell culture and GC–MS methods were employed to determine the cytotoxicity and chemical constituents of the extracts respectively.Results: Marked activity was observed in methanol(ME) fraction [MIC_(50):(0.097 7–6.250 0) mg/mL] compared to hexane and ethyl acetate fractions. Aeromonas hydrophila(environmental strain) and Shigella sonnei(ATCC 29930) were the most susceptible pathogens to ME and ciprofloxacin(Cl) at MIC_(50) value of 0.097 7 and < 0.019 5 mg/mL respectively. Cryptococcus neoformans(ATCC 66031) was susceptible to ME at 0.195 3 mg/mL compared to fluconazole at 10.000 0 mg/mL. Decreased viability of the Vero cells was observed at the concentrations of 0.1–1.0 mg/mL. The lethal dose(LC_(50))of hexane, ethyl acetate and methanol fractions were recorded at(0.30 ± 0.07),(0.52 ± 0.05) and(0.22 ± 0.04) mg/mL, respectively. Some of the compounds identified from ME were caryophyllene(25.21%), neophytadiene(11.90%), a-humulene(7.67%),phytol(4.40%), ethyl ester hexadecanoic acid(4.04%) and nerolidol(2.83%) which were known to have various antimicrobial activities.Conclusions: Methanol fraction of M. barteri is a potent and safe antimicrobial and antifungal alternative which can be useful in the search for new antimicrobial drugs. The study also confirmed the orthodox usage of M. barteri in combating infectious diseases. Objectives: To investigate antimicrobial and cytotoxic potentials as well as chemical constituents of extracts from Macaranga barteri (M. barteri). Methods: Antimicrobial activity was carried out using micro-dilution, cell culture and GC-MS methods were employed to determine the cytotoxicity and Chemical constituents of the extracts respectively. Results: Marked activity was observed in methanol (ME) fraction [MIC 50 (: 0.097 7-6.250 0) mg / mL] to hexane and ethyl acetate fractions. Aeromonas hydrophila Cryptococcus neoformans (ATCC 66031) were susceptible to ME at 0.195 (ATCC 29930) were most susceptible to pathogens to ME and ciprofloxacin (Cl) at MIC 50 (50) value of 0.097 7 and <0.019 5 mg / mg / mL compared to fluconazole at 10.000 0 mg / mL Decreased viability of the Vero cells was observed at the concentrations of 0.1-1.0 mg / mL The lethal dose (LC_ (50)) of hexane, ethyl acetate and methanol fractions were recorded at (0. 30 ± 0.07), (0.52 ± 0.05) and (0.22 ± 0.04) mg / mL, respectively. Some of the compounds identified from ME were caryophyllene (25.21%), neophytadiene (11.90%), a-humulene which are known to have various antimicrobial activities. Conclusions: Methanol fraction of M. barteri is a potent and safe antimicrobial and antifungal alternative which can be useful in the search for new antimicrobial drugs. The study also confirmed the orthodox usage of M. barteri in combating infectious diseases.