Objective To explore the clinical characteristics, diagnosis and treatment of acute urticaria with gastrointestinal hemorrhage in children. Methods The clinical data of acute urticaria with massive gastrointestinal hemorrhage during treatment in 2 cases were analyzed retrospectively, and the related literature was reviewed. Results Case 1 was an 11 -year-old boy and case 2 was a 2 -year- and 10 -month-old girl. Both of them presented with rash, abdominal pain, hematemesis and melena. After treatment, the rash basically subsided in case 1 and a little patchy rash remained in case 2 . However, both patients still had anemia of different degrees, and gastroscopy showed peptic ulcer. Both children suffered from massive gastrointestinal hemorrhage. Case 1 failed to stop bleeding effectively after drug treatment, interventional treatment and emergency surgery, and later died of secondary disseminated intravascular coagulation and multiple organ failure; case 2 stopped bleeding after medical treatment, interventional treatment and surgical treatment. Conclusions Acute urticaria is vulnerable to be complicated with massive gastrointestinal hemorrhage. After drugs, endoscopic hemostasis and surgical treatments, the bleeding can be effectively controlled. If not, serious complications are prone to occur.