Abstract: Lactobacillus species isolated from ogi, kunnu, yoghurt and palm-wine were found to produce bacteriocins. The bacteriocins had broad spectra of antimicrobial activities against both Gram-positive and negative bacteria. The effects of the bacteriocins on Escherichia coli infections in rats were evaluated. Sprague-Dawley rats were infected with E. coli and treated with 1280 AU/ml of the bacteriocins from L. plantarum MO21, L. plantarum MP12, L. casei MK21, L. casei MO11, L. brevis MK11 and L. buchneri MY21. Escherichia coli infection caused upregulation of aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, total protein, globulin, cholesterol, bilirubin and glucose levels in sera of the infected rats which were down-regulated in the bacteriocin treated rats. Gastric and GIT damage caused by E. coli infection were reduced in the bacteriocin-treated groups. Therefore, it is concluded that these bacteriocins may have useful biomedical applications.