Abstract: The ability of faecal strains of Lactobacillus acidophilus source from faeces of albino rat (Lac A), human baby (Lac B) and pig (Lac P) to prevent diarrhea induced by Shigella dysenteriae in rats is reported. These faecal strains of Lactobacillus acidophilus were found to be effective in preventing Shigella dysenteriae induced diarrhea which was obvious in the Control (C) group alone. The probiotic lactobacilli also significantly improve Feed Conversion Ratio (FCR) and Total Weight Gain (TWG) of the rats. In terms of feed consumption, rats treated with Lactobacillus acidophilus consumed 11.15 to 17.58% feed less than C to achieve the same weight. The results of serum enzymes also reveal that there was no sign of toxicological effect when probiotic lactobacillus was administered to the rats. The serum Alkaline Phosphatase (ALP) of rats dosed with Lac A, Lac B and Lac P was lower and significantly different (p<0.05) when compared with C.