Figure 2

Capsaicin cough sensitivity in COPD patients without cough, asymptomatic cougher and healthy subjects. Mean log capsaicin concentrations in 92 healthy subjects, 68 asymptomatic smokers and 42 COPD patients not complaining of cough. Note that the concentration required to induce 5 coughs is lower in the COPD patients even though they did not report troublesome cough. The values are similar to those in the smoking controls and lower than in the healthy subjects.