Upper gastrointestinal bleeding in children can be caused by variceal sources such as portal hypertension or non-variceal sources like ulcers. Initial management involves hemodynamic resuscitation and endoscopy to identify the source of bleeding. For variceal bleeding, pharmacologic therapy with vasoactive drugs and endoscopic variceal ligation or sclerotherapy can help stop bleeding. Surgical options are considered if conservative measures fail. Prognosis is poorer if the bleeding site cannot be identified, coagulation disorders are present, or significant blood loss occurs without intervention.