Food borne illnesses are infections caused by food substances or drinks consisting of harmful bacteria, viruses, parasites or even chemicals which lead to irritations in the gastrointestinal tract. Your GI tract constitutes a series of organs connected to each other to form a long, hollow tube from the mouth to the anus. While most food borne illnesses tend to be acute, which means they occur abruptly and last for a short period, there are some instances in which a food borne illness may be severe and cause debilitating complications.