Stomach pain and left abdominal pain are associated with acute gastroenteritis, gastrointestinal dysfunction, and intestinal obstruction. During an episode of acute gastroenteritis, inflammation is present throughout the mucosa of the digestive system, so patients experience pain in the stomach as well as the abdomen. As the inflammation stimulates the smooth muscles of the digestive system, it also causes spasmodic contraction of the smooth muscles and abdominal pain, which in some people is mainly manifested as pain in the left abdomen. When gastrointestinal dysfunction occurs, not only the absorption and secretion function of the gastrointestinal system will be affected, but even in serious cases, it will lead to retrograde peristalsis of the gastrointestinal system. The disease of intestinal obstruction is related to the presence of inflammation in the intestinal tract, accumulation of fecal stones, intestinal stacking and other factors. During the attack, the evacuation of the intestinal tract is affected, so the contents cannot be discharged normally, which then leads to excessive expansion of the intestinal lumen and causes abdominal pain. As the internal pressure of the intestine increases, it also affects the function of the stomach, and many people will also experience stomach pain, nausea and vomiting.