As stated previously, aspirin is contraindicated in pregnancy, gastric ulcers or bleed­ing disorders, and eosinophilic esophagitis. In order to optimize safety, asthma should be stable prior to starting an aspirin challenge procedure with a post­bronchodilator FEV1 of at least 1.5L and>70% of predicted. Spirometry is recom­mended 1–2weeks prior to the planned procedure. Exceptions to this may be made using clinical judgment in cases of xed obstructive airways or restrictive airways; however, the baseline FEV1 should ideally be less than 12% lower than the post­bronchodilator value to assure airway stability prior to the procedure. Although optional, the authors prefer to stop antihistamines for 48h prior to desensitization in order to prevent masking mild and earlier nasal reactions in favor of forcing reac­tions to occur at higher doses. Patients should refrain from using short-acting bron­chodilators for at least 12h before the desensitization (this might mask a milder earlier bronchial reaction and allow a stronger reaction to occur later), but they may continue to take their prescribed inhaled corticosteroids (ICS) with or without long­acting beta-agonists and leukotriene modiers. Leukotriene modiers will blunt the level of FEV1 decline, and their use during the procedure often prevents more seri­ous respiratory reactions from occurring during desensitization and is therefore recommended.