In Japan, “hay fever”, seasonal allergic rhinitis caused by pollen, has become more popular and has been called national affliction. Although there are less serious symptoms of hay fever, symptoms including sneezing, runny nose and itchy eye, sleep impairment, fatigue, impairment of learning and cognitive performance, have potential safety risks for flying or driving. The usage of some medications such as anti-histamines with less adverse effects on central nervous system, are approved for pilots under an appropriate regulation. However, the criteria of approval and conditions in the regulations differs from organizations in countries. In this article, we summarize current medications for “hay fever” including antihistamines, montelukast, subcutaneous and sublingual immunotherapy. We also compare aeromedical regulations for these medications between Japan and U.S.. The immunotherapy, minimizing allergic reaction for “hay fever”, may be one of the potential option for pilots.