Cigarette smoking causes injury of coronary arteries as well as other arteries. Sudden death is more frequent in heavy smokers than in non smok­ers. Studies showed that dangerous arrhythmias will be the result of effect of nicotine when injected in the animals. Carbon-monooxide is also dangerous for man when it is produced by smoking. 
The prevention of heart disease will be more satisfactory when Doctt)rs will advice patients on smoking and other risk factors. 
This advice could become one of the most re­warding activitis in medical practice. Those people who have already coronary diseases must be more careful of danger of smoking.