A non-pathogenic organism is an organism that does not cause disease when consumed or while living in a host organism. Organisms that can cause illness and disease are known as "pathogenic."
Not only are non-pathogenic organisms harmless to their hosts, they may actually be beneficial. Some research has demonstrated that non-pathogenic bacteria may inhibit the growth and reproduction of harmful bacteria, according to MedicineNet. Many non-pathogenic organisms can also live in the intestinal tracts of humans and other animals for long periods of time without causing disease or disruption. These organisms include non-pathogenic protozoa like Chilomastix mesnili, Endolimax nana and Entamoeba coli.