The antimicrobial activity of ethanol, methanol and aqueous extracts of leaf, stem and root of Acanthus ilicifolius were studied. These created an interest to test the possible antimicrobial activity of the different part of this plant, which has not been reported. The cub-plate agar diffusion method was employed to assess the antimicrobial activity of the prepared extract. Eleven test microorganisms were used in this study. Microorganism were grown overnight at 370C in the Mueller-Hinton broth at pH 7.4. The data obtained were subjected to ANOVA test to determine the significance extracts in antimicrobial activity of Acanthus ilicifolius. ANOVA test of data on the antimicrobial activity of aqueous, ethanol and methanol extracts on Bacillus megaterium, Lactobacillus plantarum, Salmonella paratyphi B, Shigella dycentreae, Escherichia coli, Streptococcus mutans, Klebsiella pneumoniae, Candida albicans, Aspergillus flavus, Staphylococcus albus, Lactobacillus acidophilus, revealed that the solvent used in extraction procedure had significant effect (P<0.05) on the level of significant observed. The inhibitory effect of the extracts on Lacto bacillus acidophillus showed no significant difference (P>0.05) between extract concentration. The most active antimicrobial parts were aqueous root, ethanol stem and methanol leaf. The ethanol, methanol and aqueous extracts of the different parts of the Acanthus ilicifolius exhibited strong to moderate activity against test microorganism. The effect exhibited by ethanol extract was significantly higher than that produced by methanol and aqueous extract. However, the length of incubation produced significant effect (P>0.05).
