Hereditary angioedema (HAE) is a noninflammatory disorder due to reduced C1-inhibitor level and/or function and characterized by recurrent, circumscribed, and self-limiting episodes of cutaneous and mucous membrane swellings involving different organs. A heterogeneous group of mutations in the C1-inhibitor gene have been found. HAE might present with diverse clinical pictures, even within families with the same mutation, but the cause of this variability is not known yet. We describe the case of type II HAE in a young adult presenting with recurrent abdominal pain for many years, occasionally associated with ascites. We suppose that an early weaning might have influenced his phenotype, making his gastrointestinal tract a "vulnerable organ," in which hereditary angioedema could express itself.