Substance P (SP), calcitonin gene-related peptide (CGRP), albumin, and histamine were measured in nasal secretions after timothy pollen challenge. The study was performed in 16 patients with allergic rhinitis. Standardized timothy antigen preparations were applied to filter papers, which were inserted into one of the nasal cavities; the contralateral side received nontreated filter papers. Nasal fluid secretion increased on both sides, more on the stimulated side than on the contralateral side. The concentrations of SP, CGRP, and histamine in the nasal fluid did not change in response to antigen challenge. The concentration of albumin increased on the stimulated but not on the contralateral side.