Allergen specific nasal challenge (ASNC) is an optimal model to study the pathophysiological mechanisms sustaining allergic inflammation, particularly the cytokine pattern. Antihistamines have been accepted as a highly effective therapy for allergic rhinitis. The aim of this double blind, randomised, placebo controlled study was the evaluation of symptoms and cytokines, during the early phase, after a single dose of mizolastine (10 mg), fexofenadine (120 mg) or placebo, using the model of ASNC. A total of 30 patients with allergic rhinitis underwent nasal challenge 6 hours after treatment. The following parameters were evaluated 30 minutes after ASNC (i.e. early phase): nasal symptoms (rhinorrhea, itching, sneezing, obstruction), and cytokine pattern, including IL1, IL6, and TNFalpha. Mizolastine was associated with early phase reduction of: i) clinical symptoms (p < 0.03), ii) cyotkine levels of IL1 (p = 0.003), IL6 (p < 0.007), and TNF_ (p < 0.003) in comparison with placebo group. Fexofenadine significantly inhibited IL6 (p < 0.004) and TNFalpha (p < 0.004) levels in comparison with placebo. The present findings demonstrate that mizolastine exerts a significant effect on early phase events, reducing symptoms and pro-inflammatory cytokines. Fexofenadine reduces TNFalpha and IL6 levels only. These effects appear to be clinical relevant for mizolastine.