Rayman RB. Irritable bowel syndrome: aeromedical considerations. Aviat Space Environ Med 2011; 82:1061–3.Irritable bowel syndrome (IBS) is a gastrointestinal disorder diagnosed in accordance with the Rome III criteria. The pathophysiology of this illness is not well defined and there are no known structural abnormalities, biomedical markers, nor inflammatory causes to explain the symptoms. There are a number of serious illnesses, such as colon cancer, ulcerative colitis, and celiac disease that mimic IBS. If the Rome III criteria are satisfied and there are no alarm features of more serious illness, an in-depth workup is not necessary. There are numerous treatment regimens for IBS, none of which are curative nor offer universal relief. Some of the treatment regimens, such as antispasmodics and antidiarrheals, are not suitable for aviators because of anticholinergic effects and sedation. The aeromedical disposition decision is always challenging because of the vagaries of this illness. In general, a more liberal policy for pilots in civil aviation would be in order as long as symptoms are not frequent nor severe and not requiring antispasmodics or antidiarrheals while flying. A more conservative policy is in order for military pilots, possibly requiring restriction to multiseat aircraft.