Mesenteric lymph node enlargement is an imaging description, but not a diagnosis of disease per se. It can be caused by the normal development of the intestinal immune system in response to events or the intestinal environment, or it can be a viral infection causing mesenteric adenitis. It is important to exclude other acute abdominal conditions such as intussusception, appendicitis, and some rare infections (TB, Yersinia). The most common is due to a viral infection. The symptoms are abdominal pain, sometimes accompanied by symptoms of gastroenteritis, i.e. diarrhea and vomiting. If you are able to drink, try to drink as much water as possible to avoid dehydration. If you vomit even after drinking, you may need intravenous fluids. Most children will heal on their own within a few days. Sometimes pain medication is needed, and when you start eating again, start with something easy to digest, such as porridge or crackers. I do not recommend random antibiotics or an IV when the child can drink. Some parents ask, “How can I recover without medication?” Are viral infections common? A normal person’s immune system produces antibodies to resist viruses. Children with low immunity sometimes need antiviral medication. The side effects are significant, and more of them are damaging to the liver.