The most common symptom of foodborne illness is diarrhea. It is a result of bacteria or virus being ingested in the body. These viruses and bacteria release toxins which initially affect the digestive system. Other symptoms include vomiting, nausea, fever, loss of appetite, abdominal cramping/pain. In severe cases, symptoms include loss of balance, mild flu, headache, jaundice, confusion, chills, and convulsions.