The common causes of diarrhea and blood in stool include enteritis, rectal polyps, bacterial dysentery, colorectal cancer and other systemic diseases. The diagnosis can be confirmed by colonoscopy, and anti-inflammatory treatment such as levofloxacin can be applied. Ulcerative colitis and other manifestations of diarrhea, mucopurulent stools, etc., it is recommended to improve the hospital colonoscopy, give mesalazine and other treatment; 2, rectal polyps: blood in the stool is the main symptom of rectal polyps, can be clearly diagnosed through colonoscopy. Daily can improve dietary habits, diet should be light, forbidden salty, spicy, generally endoscopic treatment is the main, can also choose surgery; 3, bacterial dysentery: bacterial dysentery is a kind of intestinal infectious disease, often abdominal pain, diarrhea accompanied by mucopurulent stool, when this situation, need to stool routine examination to clarify the condition. It is advisable to choose antibacterial drugs for treatment, or apply penicillin or cephalosporin antibacterial drugs, together with antidiarrheal drugs and probiotics, while replenishing electrolyte solution to ensure the balance of body fluids, which is beneficial to the recovery of the body; 4, colorectal cancer: typical symptoms of colorectal cancer are diarrhea, alternating constipation, mucus stool, blood stool, etc. It is recommended to go to the hospital for perianal finger diagnosis and colonoscopy for accurate diagnosis. If diagnosed, nutritional therapy, radiotherapy or surgery is needed; 5. Systemic diseases: such as leukemia, aplastic anemia, primary thrombocytopenic purpura and certain rare infectious diseases, such as plague and typhus, will show blood in stool and diarrhea, but in these diseases, blood in stool will be accompanied by bleeding from other parts of the body, so it is recommended to go to the hospital for routine blood and stool tests to confirm the diagnosis It is recommended to go to the hospital for routine blood and stool tests to confirm the diagnosis and undergo specialist treatment.