Thank you for asking Healthcare majic. My name is Dr Ehsan Ullah & I have gone through your query. smoking causes harm to almost every organ of the body but it basically depend upon the duration of smoking and also on quantity. smoking reduces the health of the smokers generally side effects are smoking include lung diseases, heart diseases such as coronary heart diseases , stroke and smoking can cause cancer of almost every organ of the body but quitting reduces the risks like 1 year quitting of smoking reduces your heart attack risk drop sharply and also reduced cancer risk in five years of quiting. Hope this may help you. Let me know if anything not clear. Thanks.