Escherichia coli infection may cause symptoms such as bloating and diarrhea, watery stools, urinary urgency, frequent urination, and fever. Escherichia coli is a normal flora in the intestinal tract, which is a conditionally pathogenic bacteria, and will not cause symptoms in the gastrointestinal system when the intestinal flora is in balance. When there is an imbalance of intestinal flora, due to the proliferation of harmful bacteria in the intestinal tract, Escherichia coli will have a certain impact on the intestinal system, thus inducing symptoms in the digestive system. When Escherichia coli invades the intestinal system, it causes dysfunction in the secretion of the small intestine, but not in the intestinal mucosa, and the patient will have symptoms such as bloating and diarrhea due to the disruption of absorption and secretion in the small intestine. Patients excrete stools with excessive water content, mainly watery stools, and most of them are not accompanied by mucus pus and blood because the intestinal mucosa is not damaged. In the state of long-term low immunity, Escherichia coli will move to other parts of the intestinal tract, and once it multiplies in the human urethra and bladder, it will also cause urinary symptoms, mainly urinary urgency, urinary frequency, stinging sensation of urine, and many patients will also have fever symptoms.