Single-blind, cross-over comparison of standard doses of ipratropium bromide (2 puffs of 0.02 mg each) and fenoterol (2 puffs of 0.2 mg each) in 36 pairs of experiments in 6 patients with partially reversible airway obstruction, presumably secondary to chronic widespread pulmonary tuberculosis, revealed no difference between the drugs in bronchodilating effect, evaluated by peak-flow measurements and spirometry. The inhalation of isoprenaline at the end of the experiment induced no further improvement in the lung function variables measured. The results suggest that a vagal reflex mechanism plays a major role in bronchoconstriction connected with severe chronic pulmonary tuberculosis.