Background: Gulf War Illness (GWI) results in tremendous impact to quality of life. Symptoms of chronic rhinosinusitis (CRS) and fatigue are the first (47%) and third (41%) most common symptoms of patients with GWI, respectively. These symptoms are biologically characterized by a milieu of elevated levels of proinflammatory cytokines; to date, the profile of these cytokines in serum and nasal secretions is incompletely understood and has not been assessed in response to therapy. Nasal irrigation (NI) is a therapy which bathes the nasal cavity with a solution (liquid). There are two promising forms of NI; saline NI (S-NI) is hypothesized to improve sinus symptoms by thinning and clearing mucus and inflammatory mediators, decreasing mucosal edema and improving ciliary function. Xylitol NI (X-NI) has been shown to change the salinity of the mucosal surface resulting in enhanced antimicrobial properties. Although NI is an evidence-based adjunctive therapy for CRS and has been reported to be effective for CRS and fatigue, it has not been assessed in a GWI population.