Chronic idiopathic urticaria (CIU), characterized by the appearance of itchy wheals of unknown etiology, can be extremely debilitating and can significantly reduce a patient's quality of life (QOL). Fexofenadine, a non-sedating, H1-receptor selective, long-acting antihistamine, is licensed worldwide for the treatment of CIU. A number of dose-ranging studies have evaluated the efficacy and safety of fexofenadine for the the treatment of CIU. In two similar North American studies, patients received either fexofenadine HCI (20, 60, 120, or 240 mg bid) or placebo. All four doses of fexofendine were statistically superior to placebo at reducing pruritus and reducing the number of wheals (P < or = 0.0238). A dose-finding study undertaken in Japanese patients confirmed that fexofenadine HCI (60 mg and 120 mg bid) is an effective treatment for CIU. A similar dose response was shown in all three studies when the results were compared. Furthermore, health outcome analyses of the North American studies indicated that fexofenadine HCI 60 mg bid significantly improved patient's QOL. In these studies, fexofenadine had a consistently comparable safety profile to placebo, with no dose-related trends in the incidence of adverse events. In conclusion, fexofenadine is an effective and well-tolerated treatment for CIU, with a wide therapeutic window. Importantly, the lack of ethnic differences between the studies from North America and Asia indicate that the efficacy and safety of fexofenadine demonstrated in these studies are cross-culturally applicable.