Participants with asthma are randomly assigned to a 15-min (phenylethyl alcohol) odor inhalation, accompanied by either an asthmogenic suggestion (nocebo), or a therapeutic suggestion (placebo). Airway inflammation, lung function, and asthma symptoms are measured in response to the odor/suggestion, up to 24 hours after odor inhalation. The investigators are also measuring worry and heart rate variability as potential mediators of the response.