Two mechanisms underlying the onset of angioedema have been proposed7: first, the mast cell-mediated pathway where chemical mediators (e.g., histamine and leukotriene) released from the mast cells increase the dilation and permeability of blood vessels and second, the bradykinin (BK)-mediated pathway where BK—a potent vasoactive substance—directly affects vascular permeability via its B2 receptor and also stimulates the release of the vasoactive peptide substance P (SP) from sensory nerves8. Here, TFF2 is linked to angioedema.