Early-(ER) and late-phase reactions (LPR) occur in the nasal mucosa with release of in¬ flammatory mediators and a mixed cellular influx. In a preliminary study, we evaluated ten atopic subjects with confirmed allergic rhinitis (age range 29-45 years) and five nonatopic controls (age range 35-53 years) by nasal provocation with 10 to 1,000 protein nitrogen units (PNU) of grass or ragweed extract. In 80% of all patients, symptom scores for sneezing rose during the ER after one hour and LPR after 3 to 8 hours from a mean baseline of 0.2 to 4.9 (ER) to 3.7 (LPR). Other symptoms for rhinorrhea, nasal congestion, and pruritus rose in 80% to 90% of all patients from a mean of 2.8 to 15.1 (ER) and 2.8 to 3.7 (LPR). Nasal al¬ bumin levels rose during the ER from 52 to 102 µg/L but less at LPR to 58 µg/L (p < 0.05). Nasal histamine rose after 10 minutes into challenge from 2.8 to 4.2 ng/ml and peaked over LPR from 4.5 to 11.0 ng/ml. Nasal interleukin-1 (IL-1) levels increased from 3 to 6 hours approaching diluent control during the LPR, which paralleled a rise in nasal epithelial cells. Nasal IL-8 levels at 3 and 6 hours during the LPR from 119 to 178 pg/ml corresponded to nasal smear neutrophilla from X of 3.5% to 11.6%. Thus, nasal provocation allergic rhini¬ tis is a useful tool to monitor nasal cytokine mediators and new therapeutic agents.