Larch Arabinogalactan (ARG) effectively inhibits the attachment of pathogenic E.coli into animal intestinal epithelium and intestinal mucus, decreases the presence of fecal Salmonella cultures and rotavirus, prevents the appearance of diarrhea or quickly reduces the existing one, scientifically slows the growth rate of gastrointestinal pathogens, reduces the need for antibiotics and anti-parasitic medicaments, decreases detrimental bacteria and putrefactive compounds, reduces environmental impact.