Abstract
Four methods of smoking withdrawal were compared in patients with smoking related diseases attending a hospital or chest clinic. Reinforcing verbal advice with a booklet or with a booklet together with nicotine or placebo chewing gum did not result in greater success than verbal advice alone. Roughly a quarter of those patients who denied smoking had carboxyhaemoglobin and plasma thiocyanate concentrations typical of smokers. At the end of a year 150 out of 1550 patients (9.7%) had successfully stopped smoking.