The authors describe the results of a study of a group of children suffering from allergic rhinitis; the Authors evaluated eosinophils, basally and after nasal provocation test. Both clinical and cellular responses were evaluated. The basal results were: presence of eosinophils in 9/17 (52.9%) subjects allergic to Graminacee, in 42/61 (68.3%) subjects allergic to Dermatophagoides and in 3/3 (100%) subjects allergic to Parietaria. The results of the clinical response are the following: Graminacee: positive response in 20/22 (90.9%) tests; Dermatophagoides: 48/63 (76.2%); Parietaria: 6/6 (100%). The results of laboratory response are the following: Graminacee: positive response in 14/18 (77.8%) tests; Dermatophagoides: 45/59 (76.3%); Parietaria: 5/5 (100%). The evaluation of both responses is useful to increase the sensitivity of the nasal provocation test.