Diarrhea is a common symptom of rectal cancer. For symptomatic treatment, we can take medications such as montmorillonite powder or loperamide to alleviate diarrhea, and use probiotics like Bifidobacterium triple or quadruple live bacteria to regulate intestinal flora. However, these treatments only alleviate symptoms rather than cure the underlying disease. The key is to control the rectal cancer itself. Treating the tumor is the fundamental solution. Only when the tumor is under control will the patient's diarrhea symptoms be relieved. Otherwise, even if the symptoms are alleviated by antidiarrheal drugs, if the tumor is not controlled, symptoms including diarrhea, rectal bleeding, and abdominal pain will recur and may even worsen.