Abdominal pain is one of the common symptoms in pediatrics, mostly caused by organic or functional lesions of abdominal organs and tissues, but can also be caused by extra-abdominal diseases; diagnosis is the basis for treatment, so it is especially important to improve the accuracy and speed of diagnosis of the cause of abdominal pain. Characteristics of abdominal pain in children Children’s narratives of abdominal pain are unclear and do not express well the site, nature, and events of abdominal pain, which can make diagnosis and treatment difficult. In particular, it is important to note that acute abdominal illnesses must be treated urgently and can endanger the child’s life if diagnosed incorrectly or treated improperly. Infants: expression of abdominal pain is a major problem, with facial expressions related to the degree of pain, such as frowning, squeezing of the eyes, nostrils dilated, pouting of the mouth, distorted corners of the mouth, and jaw tremors, and crying with a frequency and tone different from the “cry” of fright or anger; toddlers and preschoolers: have the initial ability to express abdominal pain, but accuracy is poor and assessment still needs to be done with caution. Preschool children: the expression of abdominal pain is more accurate, and as they grow older, the limitation of pain tends to become obvious. Common diseases: a. Acute appendicitis Most commonly seen in children aged 4-12 years, abdominal pain at the onset is mostly located around the umbilicus or in the upper abdomen, shifting to fixed right lower abdominal pain after 6-12 hours; may be accompanied by fever, nausea, vomiting; obvious pressure pain in the right lower abdomen, elevated blood leukocytes, CRP; common acute abdominal disease in children, requiring timely hospital consultation. Second, acute gastroenteritis with eating irritating food or indigestible food triggers, manifested as abdominal pain, vomiting, diarrhea, accompanied by abdominal distension, hyperactive intestinal sounds. III. Intestinal obstruction The manifestation is paroxysmal crying and abdominal pain, accompanied by vomiting food or bile and stopping defecation and exhaustion; positive and lateral abdominal radiographs can make a clear diagnosis. Intussusception Most often seen in infants and young children under 2 years old, with rapid onset, sudden crying and restlessness, pale face, twitching of hands and feet, repeated abdominal pain, quiet as usual during remission, with jam-like stools and abdominal masses; ultrasound of intussusception can help diagnose. V. Mesenteric lymphadenitis Most often occurs when you have a cold, in addition to fever, runny nose and sore throat symptoms, the child has pain around the umbilicus, and the abdominal pain will gradually disappear when the child gets better from the cold. Sixth, intestinal spasm belongs to functional abdominal pain, the degree of abdominal pain varies, heavy may have pale face, cold limbs, general condition is better, with the age of most children abdominal pain relief or disappear. Seven, intestinal roundworm disease, mostly due to children’s dietary hygiene habits, children often have repeated periumbilical pain, decreased appetite, nausea, vomiting, and grinding teeth, sleep disturbance, irritability and other manifestations, the application of deworming drugs, abdominal pain can disappear. Allergic purpura The incidence of allergic purpura in children has increased in recent years, which is a metabolic disease, manifested as skin purpura of different sizes, mostly distributed in the lower limbs and buttocks, accompanied by paroxysmal severe abdominal cramps, obvious around the umbilicus and lower abdomen, with pressure pain, but the abdomen is soft, there may be diarrhea, blood in the stool, need to be promptly hospitalized. Urinary tract diseases Urinary tract infections and stones can cause abdominal pain, physical examination abdominal signs are not obvious, urinary routine changes help to diagnose; scrotal emergencies such as testicular and adnexal torsion, sometimes also due to complaints of abdominal pain, such as delayed diagnosis and treatment for more than 6 hours, will bring the adverse consequences of testicular necrosis resection. Ten, pediatric defecation disorders including infant defecation difficulties, functional constipation, functional fecal retention, functional dyspepsia, irritable bowel syndrome, etc.