The most common diseases that cause pain below the right side of the belly button are the following: i. If a patient has appendicitis, it will manifest as pain below the right side of the belly button. Appendicitis includes acute appendicitis and chronic appendicitis. The degree of pain varies, from vague pain in some patients to severe distension, often accompanied by abdominal distension and fever, and patients are advised to improve routine blood tests, appendix ultrasound or CT examination. Second, female patients with pain below the right side of the navel should be alert to adnexal diseases, such as adnexal inflammation, adnexal tumors, etc. It is recommended that patients go to the gynecology department for specialist consultation. If a patient has colorectal cancer, it can be manifested as pain below the right side of the navel, often accompanied by blood in the stool, diarrhea, and a feeling of urgency, it is recommended to improve colonoscopy. If the patient has urinary system diseases, commonly urinary stones may also show pain below the right side of the navel, often accompanied by right lumbar pain, suggesting the patient to improve routine urine examination, urinary system ultrasound or CT examination.