If you have diarrhea for three days, you should go to the hospital for stool routine and colonoscopy to find out the cause of the diarrhea. Common causes of diarrhea are bad habits, intestinal inflammation, tumors, etc. The causes can be clarified and then targeted to regulate or give levofloxacin, mesalazine and other medications, surgical treatment, and so on. 1. Bad life habits: such as overeating, overeating, eating spicy and irritating food, can cause adverse stimulation to the intestinal tract, causing spasmodic contraction of the intestinal tract and diarrhea. Symptoms can be relieved by improving lifestyle and adjusting dietary structure. 2. Intestinal inflammation: such as acute and chronic enteritis, ulcerative colitis, etc., due to the presence of intestinal inflammation, can form a stimulus to the mucous membrane, resulting in diarrhea, sometimes accompanied by abdominal pain and other symptoms. The diagnosis can be confirmed by routine fecal examination, followed by medication such as levofloxacin, mesalazine and so on. 3. Intestinal tumor: such as rectal cancer, colon cancer and other tumors can form pressure on the intestines and stimulate the intestinal mucosa causing diarrhea and other symptoms, which can be diagnosed by colonoscopy, and then appropriate surgical treatment and chemical treatment can be given according to the condition of the disease. If you have diarrhea for three days, there may be other reasons, so you should go to the hospital in time and do the relevant examination to clarify the cause of the disease and guide the treatment.