A stomach virus is a viral infection that affects the digestive system; this is also known as viral gastroenteritis. Food poisoning is caused by contaminated food that has spoiled, been unhygienically prepared, or has been corrupted in any way. Food poisoning is most commonly caused by bacteria, but it can also be caused by viruses, and less commonly parasites. The symptoms of a stomach virus include: • Diarrhea that may be watery or bloody • A loss of appetite • Nausea or vomiting • Stomach cramps, muscle aches, or weakness • Low-grade fever • Headaches • Light-headedness or dizziness The symptoms of food poisoning include: • Watery or bloody diarrhea • Nausea • Vomiting • Stomach pain and cramping • A fever, chills, and body aches • Dizziness and lightheadedness from dehydration