The antibacterial and phytochemical effects of aqueous extracts of Moringa oleifera roots on E. coli challenged broiler chicks were investigated. Ninety one-day oldbroiler chicks were orally inoculated with E. coli at 1.23×10⁸ CFU/ml and then divided into six treatment dose levels: 5g/l, 10g/l, and 15g/l Moringa root extract (MRE), positive control, negative control and a standard (commercial antibiotics). The extract showed no significant difference (P>0.05) in performance, carcass and nutrient retention indices of birds compared to the controls. However, at 10g/l dose level, serum parameters including cholesterol and uric acid were higher (P<0.05) at 118.9Mmol/l and 4.07Mmol/l respectively, but lower in total protein (4.40g/l, P<0.05). Birds fed 15g/l dosage had lower (P<0.05) serum cholesterol level (77.503Mmol/l) and lower (P<0.05) mortality (1%) compared to other treatments (2.2–3.3%) and the negative control (5.5%). The findings of this study suggest that the active ingredients from Moringa oleifera roots could significantly assist in combating endogenous pathogenic activities.