Zir-Fos is a dietary supplement composed of a symbiotic and B-complex vitamins. A symbiotic is a mixture of a prebiotic (fructo-oligosaccharides) and a probiotic (Bifidobacterium longum BB 536).

Dietary supplementation with prebiotics/probiotics (symbiotic action) and vitamins is effective in restoring intestinal flora in situations where it is unbalanced due to: acute infectious diarrhea, diarrhea associated with antibiotic use, diverticular disease of the colon, constipation, and irritable bowel syndrome.