In this study we have compared the levels of IgG1 and IgG4 autoantibodies to IgE in the sera of patients with allergic rhinitis and non-allergic rhinitis. A group of patients undergoing cosmetic nasal surgery, but who did not have rhinitis or any history of atopy, acted as control. The frequency of positive titres of IgG1 and/or IgG4 anti-IgE was 70% (14/20) in patients with allergic rhinitis, 50% (10/20) in patients with non-allergic rhinitis and 20% (4/20) in the control group. The mean titres of IgG1 anti-IgE and IgG4 anti-IgE were in the order allergic rhinitis > non-allergic rhinitis > controls. In the allergic rhinitis group levels of IgG1 anti-IgE (P = 0.0055) and IgG4 anti-IgE (P = 0.0028) were significantly higher than those found in the control group. The non-allergic rhinitis group also showed significantly higher levels of IgG1 anti-IgE (P = 0.0182) and IgG4 and anti-IgE (P = 0.0359) than the control group. The existence of IgG autoantibodies to IgE in both allergic and non-allergic rhinitis suggests a possible role for these antibodies in the disease process, particularly in patients whose symptoms are not due to an allergic trigger.