Most cases of abdominal pain in children are caused by minor problems, such as stomach flu or constipation, and home treatment usually is all that is needed to relieve them.

The most common causes of abdominal pain in preschool- and school-age children include:

• Stomach flu (gastroenteritis), which can be caused by infection with certain types of bacteria or viruses or by some poisons.
• Constipation.
• Injury to the abdomen, such as from a fall or a blow to the stomach.
• Appendicitis. Appendicitis is more common in children older than age 5 than in babies and toddlers.
• Pain related to normal bowel activity (peristalsis).

Less common causes of abdominal pain in preschool- and school-age children include:

• Bladder infections (urinary tract infections), which are usually caused by bacteria in the bladder.
• Inguinal hernia, which may be present at birth or develop because of surgery or violent or chronic coughing.
• Strep throat, which is caused by a bacterial infection.

Rare causes of abdominal pain in this age group include:

• Cystic fibrosis, which may interfere with the way nutrients are absorbed from the digestive tract.
• Kidney stones, which can cause severe pain as they break loose and travel to the bladder or out of the body.
• Pancreatitis, which can cause severe pain in the upper part of the abdomen.
• Peptic ulcer disease, which are crater-shaped sores that develop when the digestive juices produced by the stomach eat away or erode the lining of the digestive tract.
• Sexual abuse.
• Sickle cell disease, which causes pain when blood flow to the organs in the abdomen is blocked.