 The protocol involves a 4-week, double-blind, placebo-controlled parallel-design trial of oral ifetroban in patients with AERD. At the end of the 4-week treatment phase ifetroban or placebo each subject will undergo a graded oral aspirin desensitization procedure in order to initiate high-dose aspirin therapy, which is standard-of-care at our institution and is the only available therapy known to modify the course of AERD. 