BACKGROUND There have been few studies about the effect of histamine on ciliary beat frequency (CBF) in the acute phase of allergic rhinitis. OBJECTIVE The present study was designed to investigate CBF in the acute phase of allergic rhinitis and the effect of histamine on CBF. MATERIALS AND METHODS Nasal septal mucosae were obtained from 13 mice that had been systemically immunized and locally challenged with ovalbumin (OVA) (group A), 11 OVA immunized and phosphate-buffered saline-challenged mice (group B), and 12 nontreated negative control mice (group C). The CBFs were observed within 20 minutes of local challenge with OVA. Ciliary beat frequencies were measured before and after treatment with 10(-5), 10(-3), and 10(-1) mol/L histamine and after administering antihistamine or Dulbecco's modified Eagle's medium to histamine-exposed mucosa. RESULTS The baseline CBF in group A was higher than in groups B and C. After treatment with 10(-1) mol/L histamine, CBF in all groups decreased to 0 within 5 to 7 minutes, whereas treatment with 10(-5) or 10(-3) mol/L histamine had no effect. The application of 100 μmol/L fexofenadine or Dulbecco's modified Eagle's medium solution restored histamine-induced ciliostasis to near baseline CBF after 10 minutes. CONCLUSIONS Ciliary beat frequency increased in the acute phase of a mouse model of allergic rhinitis. Physiologic concentrations of histamine had no effect on CBF, and thus, it appears that other mechanisms control CBF in the acute phase of allergic rhinitis.