In a controlled randomised trial we analysed whether the use of the term "smoker's lung" (Danish: "rygerlunger") instead of chronic bronchitis when talking to patients with chronic obstructive lung disease (COLD) changed their smoking habits. Fifty-six smoking patients with COLD were allocated to either intervention (n = 25) or control groups (n = 31). In the intervention group the lung disease was designated smoker's lung in all communication with patients about their illness and in the control group traditional terminology was used. All patients were given the same medical treatment and the same encouragement to stop smoking. One week after discharge 57% had stopped smoking in the smoker's lung group vs 26% in the control group (p = 0.028), at three months 50% vs 19% (p = 0.027) and at one year 40% vs 20% (p = 0.148). Referring directly to the cause of a self-inflicted illness may be an effective way of discouraging risk behaviour, at negligible cost.