We investigated the effects of rhinovirus (RV) infection on airways reactivity. Twenty seven normal volunteers (11 atopic) were inoculated with RV 2 or RV EL. The provocative concentrations of histamine and bradykinin required to produce a 15% fall in the forced expiratory volume in one second (FEV1) (PC15FEV1) were measured before, 7 and 21 days after inoculation. Infection was determined by a fourfold rise in anti-viral antibody titre and by viral culture from nasal washings. Peak expiratory flow rate (PEF) was recorded three days before and for 21 days after inoculation. All subjects underwent the first two bronchial challenges, and 22 the third challenge. For the whole group and for atopic subjects, there were significant correlations between the PC15 values for bradykinin and histamine (r = 0.82 and r = 0.85, respectively). Twenty subjects were infected; six had clinical colds. For the 16 infected subjects who had all three challenges, the median (range) PC15FEV1 for the histamine challenges was 36 (0.89-64), 62 (1.5-64) and 34 (0.94-64) mg.ml-1, respectively, and 32 mg.ml-1 for each bradykinin challenge (range: 0.015-32, 0.088-32 and 0.033-32). There were no significant differences between study days for PC15FEV1 histamine or bradykinin for the whole group, the infected subjects, those with clinical colds or for those infected with either RV subtype. There was no significant change in mean daily PEF after viral infection. We conclude that airways reactivity to histamine and bradykinin is unchanged after experimental RV infection in normal volunteers.