Increased exhaled nitric oxide (NO) may reflect respiratory tract inflammation in untreated asthmatics. We compared exhaled NO and bronchoalveolar lavage (BAL) nitrate/nitrite (NO3-/NO2-) in 10 patients who had untreated, active pulmonary sarcoidosis with those of normal control subjects. Exhaled NO concentrations, determined by chemiluminescence, were similar in patients and control subjects (peak NO concentration of patients [mean +/- SD]: 13.6 +/- 5.9 parts per billion [ppb], peak NO concentration of control subjects: 11.2 +/- 5.7 ppb, p = 0.32; mean alveolar NO concentration of patients: 7.8 +/- 4.4 ppb, mean alveolar NO concentration of control subjects: 7.1 +/- 4.2 ppb, p = 0.70; end-tidal NO concentration of patients: 6.9 +/- 4.5 ppb, end-tidal NO concentration of control subjects: 6.6 +/- 4.0 ppb, p = 0.60). BAL NO2- was assayed using a modified Griess reaction after reduction of NO3- to NO2-. There was no significant difference in mean BAL NO2- concentrations, expressed as nanomoles per milliliter of epithelial lining fluid (patients: 544 nmol/ml, control subjects: 579 nmol/ml, p = 0.81) or as nanomoles per milliliter of BAL fluid (patients: 6.7 nmol/ml, control subjects: 5.7 nmol/ml, p = 0.41). These data suggest that excess NO generation does not accompany the respiratory tract inflammation of pulmonary sarcoidosis.