There are many causes of low-grade fever and pain around the umbilicus in the elderly, including inflammatory factors, intestinal dysfunction and tumor diseases. 1. Inflammatory factors: this is a relatively common cause in the elderly, such as appendicitis, enteritis, etc. will cause vague pain around the umbilicus and low-grade fever symptoms. 2. Intestinal dysfunction: when the intestinal dysfunction is caused by improper diet, cold, insufficient intestinal power, etc., the symptoms such as vague pain and low fever around the umbilicus will also occur. 3. Tumor: when patients suffer from adenocarcinoma of small intestine and other diseases, it will often cause vague pain and fever around the umbilicus. For specific reasons, it is necessary to go to regular hospitals to improve the relevant examination, after clarifying the causes, under the guidance of doctors, targeted treatment.