Background: Angiotensin Converting Enzyme inhibitors (ACEi) may cause angioedema, with an incidence of 0.1% to 1%, which may be life-threatening. ACEi induce angioedema by increasing the levels of bradykinin. Angiotensin II receptor blockers (ATRB), have a pharmacological profile similar to ACEi. The polymorphism of the ACE gene is based on the presence or absence of a 287-bp element on intron 16 on chromosome 17. The plasma level of ACE is related to gene polymorphism. ACE level in genotype DD is double that in genotype II.