A toxin is a non-biological substance, causing disease in humans. Many toxins are food-borne and of natural origin. There are literally thousands of food-borne toxins, however, only a few cause outbreaks (e.g. shellfish toxins) or are of importance for public health (e.g. mycotoxins).

Food-borne man-made toxins (i.e. pesticides etc) are not included in this section.