The effect of advice to stop smoking on arterial disease patients, assessed by serum thiocyanate levels.

Serum thiocyanate has shown itself to be useful in distinguishing smokers from non-smokers. Our anti-smoking attitude resulted in 12 out of 32 smokers stopping smoking during the trial. Further, our evidence suggests that a patient who says he has given up smoking entirely can probably be believed, but a claim to have reduced smoking may be less reliable.