Continuous diarrhea for three or four days, you should promptly go to the hospital, seek medical help, under the guidance of the doctor to clarify the cause of the disease, and according to the patient’s specific condition to give the cause of the treatment, symptomatic treatment and so on. Diarrhea is defined as increased frequency of bowel movements, increased volume of feces, unformed, loose or liquid, sometimes containing pus and blood or with undigested material and fat. The causes of diarrhea are many, not only the intestinal tract itself can be caused by diseases, but also extra-intestinal and even systemic diseases and injuries can cause diarrhea. 1. Treatment: For antibiotic-associated diarrhea, antibiotics should be stopped immediately or the original antibiotics should be adjusted, and probiotics, such as bifidobacteria, can be added as prescribed by the doctor. For lactose intolerance, the lactose in food should be eliminated. For diarrhea caused by gastrointestinal malignant tumor, the tumor can be surgically removed after completing the necessary auxiliary examinations. 2. Symptomatic treatment: when diarrhea for three or four days, the intestinal fluid will be discharged along with feces, and the intestinal fluid contains electrolytes and other liquid components, so after the loss of intestinal fluids, the patient may suffer from dehydration, electrolyte disorders and other conditions. For this situation, it is necessary to actively replenish fluids, correct dehydration, electrolyte disorders, and supplement vitamins, amino acids, fat milk and other nutrients as appropriate. Patients should follow the doctor’s instructions to actively cooperate with the doctor’s treatment, do not blindly treat yourself, so as not to delay the condition or cause adverse reactions.