The causes of abdominal pain, diarrhea, wasting and weakness are as follows: 1. Inflammatory bowel disease, such as Crohn’s disease, ulcerative colitis, etc., mainly manifesting as abdominal pain, diarrhea and recurrent episodes of mucopurulent stools, which can be diagnosed through colonoscopy. 2. 3, intestinal malignant tumor, the disease can cause abdominal pain, diarrhea, loose stool or black stool, weight loss and other symptoms, patients mostly have a family history of gastrointestinal tumor, the diagnosis can be clarified by colonoscopy or abdominal enhancement CT. If the above symptoms persist for a long time, it is recommended to visit the gastroenterology department of the hospital in time.