The constant vague pain on the left side of the belly button is not necessarily a precursor of cancer, but it may be pancreatitis, gastroenteritis and other diseases. The cause of the constant vague pain on the left side of the navel needs to be considered as a high possibility of lesions in the kidney area, ureter, and ascending colon. If the pain is female, consider a possible correlation with gynecological diseases. If the left side of the abdomen is accompanied by diarrhea, constipation and other gastrointestinal symptoms in addition to hidden pain, the possibility of intestinal lesions should be considered, and the possibility of functional gastrointestinal disorders due to slow peristalsis should be considered. In addition, a cold abdomen or a slight muscle strain on the left side of the navel can also cause vague pain on the left side of the navel. In case of the above, you should go to the internal medicine department of the hospital for examination as soon as possible to avoid delaying the condition. In general, eat more light food, less greasy food, do not drink strong tea or alcohol, and pay attention to eating warm food, not cold food.