The result of this study has provided the evidence for the use of Moringa oleifera extract for protection and modulation of the immune system in controlling Newcastle disease especially in free-ranging village flocks, which represent more than 80 percent of the total poultry population in some countries, and also for the use of herbal products to improve the immunity of pet, livestock, and human population. This also has offered a novel avenue of modulating the immune system in order to help in preventing livestock and human infectious diseases.