Hereditary angioedema is caused by a defect in C1 inhibitor activity (C1INH). Its occurrence is rare and it is associated with an autosomal dominant mode of inheritance. We describe seven patients (4M:3F), age from 12 to 50 years old, who are affected by hereditary angioedema; four of them belong to the same family. The main clinical manifestations were: angioedema of face, hands and feet (6/7) and abdominal pain (2/7). No triggering factors were associated with symptoms in 4/7 patients and trauma (2/7) and menses (1/7) were reported in the other three ones. One patient was submitted to laparotomy for partial intestinal resection, before diagnosis. Laboratory complement analysis revealed the absence of hemolytic function of complement, reduced C4 (6/7) and low C1INH levels. All patients received Danazol (100 mg/day) with clinical control. Hereditary angioedema has to be considered in the differential diagnosis of angioedema, since an early diagnosis of this immunodeficiency, leading to specific treatment in order to decrease the complications.