http://1.bp.blogspot.com/-kCXpjft1SCk/T2DgOYXjWPI/AAAAAAAAADk/F2SkzqxTOMI/s1600/no+smokin g+2.jpg The ill effects of cigarette smoking are numerous,the most dangerous being coronary heart diseases,lung diseases,peripheral vascular diseases,urinary bladder cancer,lung cancer,esophageal cancer,premature ageing of skin,the list is endless so is the chemical composition of cigarette smoke http://2.bp.blogspot.com/-inazcRJLZhM/T2Dh_mJvgXI/AAAAAAAAADs/6GwZwaQOQvw/s1600/cigarette +smoke.jpg So cigarette smokers are at higher risk of getting those diseases ,most of which are attributed to the presence of nicotine in the cigarette smoke. Is there any disease affecting non-smokers only or more prevalent in non-smokers ? Ulcerative colitis is a chronic inflamatory disease of the colon (large intestine) with unknown cause.It is characterised by inflamation and sore (ulcers) in the inner lining of the large intestine and rectum.The most common symptoms are are chronic diarrhoea mixed with blood .It is now accepted that ulcerative colitis predominantely affects non-smokers and former smokers and the course of disease is more benign in non-smokers. How nicotine exerts protective effect against ulcerative colitis? It may have inhibitory effect on body immune system. Excessive production of mucous in the intestinal wall( decreased in ulcerative colitis)which protects the intestinal wall from bacterial invasion and also from the breakdown products of food. Shall we recommend cigarette smoking? http://2.bp.blogspot.com/-iC0N2c7K9ww/T2Dr5rE_54I/AAAAAAAAAD0/TJdpqCViKQM/s1600/abcdefg.j pg If you are reading this post, feel free to leave your comment.