The microbiota of the human gastrointestinal tract plays a key role in nutrition and health. A delicate balance exists between the human intestinal microflora and its host. Upset of this community structure may lead toward undesirable immune reactions. Many different environmental factors may affect the gut and urogenital microbial ecology; these include diet, medication, stress, age and general living conditions. It is therefore important that gut microflora interactions be controlled and sustained with probiotics and prebiotics. Lactobacilli strains have been investigated for their ability to support various aspects of human health. Specifically, they have been looked at for their effects on the female microbiota and yeast defense. L. rhamnosus has been clinically researched for its ability to support the female system by increasing desirable lactobacilli and decreasing undesired microflora. L.casei has been shown to support healthy bladders. Bifidobacteria is useful for gastrointestinal support and Streptococcus can help support immune function within the intestinal tract. scFOS, also called short chain fructooligosaccharides, are prebiotics that have short molecular chains. They function as non-digestible fiber that can positively affect selected groups of beneficial intestinal microflora, such as lactobacillus. While probiotics merely add beneficial microflora, prebiotics influence the intestinal environment so that beneficial colonies of microflora can flourish. By aiding the beneficial microflora’s survival, pathogenic microflora can have a decreased chance of survival.