3-year-old baby belly button pain may be due to intestinal inflammation, appendicitis or cystitis and other causes, must promptly seek medical attention. 1. intestinal inflammation: when the baby’s intestinal tract is infected by bacteria or viruses will trigger enteritis, due to bacteria, viruses will cause irritation of the intestinal mucosa, which will lead to pain below the navel, sometimes accompanied by diarrhea. 2. Appendicitis: when the baby suffers from appendicitis, with the aggravation of the symptoms, due to the stimulation of the inflammation will sometimes cause persistent or paroxysmal pain below the navel or even around the navel. 3. cystitis: due to bacterial infection will cause irritation of the bladder wall, sometimes it will cause pain under the navel, and even cause frequent urination, urinary urgency, fever and other symptoms. 3-year-old baby belly button pain may be caused by a variety of reasons, it is recommended that timely medical examination, under the guidance of the doctor on the cause of treatment, so as not to delay the condition.