Rotavirus is a virus that infects the bowels. Rotavirus is the most common cause of severe diarrhea among infants and children throughout the world and causes the death of about 500,000 children worldwide annually. Lactobacillus acidophilus occurs naturally in the human and animal gastrointestinal tract and mouth. Some strains of L. acidophilus may be considered to have probiotic characteristics. L. acidophilus produces bacteriocin CH5 that is both antibacterial and inhibitory against certain yeasts and molds and is effective against both Salmonella typhimurium and Campylobacter jejuni. It has been shown to have a preventative effect against traveller's diarrhea. L. acidophilus has significant immuno- potentiating effects and may be used as a safe oral adjuvant for rotavirus vaccines in neonates.