Diarrhea refers to diarrhea. Diarrhea is not contagious if it is caused by non-infectious factors; it may be contagious if it is caused by infectious factors such as bacillary dysentery. Diarrhea caused by non-infectious factors is usually diarrhea caused by a poor diet or exposure to cold. Diarrhea caused by this condition is usually not contagious and the symptoms are mild and can be relieved by prompt antidiarrheal treatment. If the diarrhea is caused by infectious factors, such as bacillary dysentery, the diarrhea is caused by Shigella bacteria that attack the intestinal system. It is a disease caused by the invasion of the mucous membrane of the intestinal system by Shigella bacteria. Since Shigella bacteria are contagious, there is a certain possibility that contact with the patient during the period of the disease will lead to the transmission of the disease. If the patient has diarrhea, it is recommended to go to the hospital in a timely manner, after identifying the cause of the disease, the doctor will take targeted treatment according to the cause of the disease.