Understanding Stomach Bug Symptoms And Treatment Options A stomach bug, or viral gastroenteritis, is a common illness that affects the digestive system, causing symptoms like nausea, vomiting, diarrhea, and stomach cramps. It is typically caused by viruses such as norovirus or rotavirus but can also result from bacterial or parasitic infections. The condition spreads through contaminated food, water, or close contact with an infected person, making it contagious. Symptoms can range from mild discomfort to ...