Stomach infection, also known as gastroenteritis, is an intestinal infection that can be caused by a virus, bacteria, or parasite. The most common symptoms of gastroenteritis include watery diarrhea, stomach cramps, nausea or vomiting, and sometimes fever. Inflammation in the stomach and intestines causes these symptoms, which can be very unpleasant but usually clear up by themselves within a week. Gastroenteritis can affect people of all ages, but it is particularly common in young children. The infection can be spread through contact with an infected person or by consuming contaminated food or water. People with weakened immune systems, such as infants, older adults, and those with compromised immune systems, are at a higher risk of developing complications from gastroenteritis. There is no effective treatment for viral gastroenteritis, so prevention is key. To prevent gastroenteritis, it is important to avoid food and water that may be contaminated and to wash your hands thoroughly and often.