The major health problems caused by smoking include, in various degrees A compromised immunity Cancer Heart disease Lung diseases Diabetes Erectile dysfunction Chronic obstructive pulmonary disease Poor vision Skin, nail and hair infections including skin cancer Mouth ulcers and mouth cancer Asthma and chronic cough Tooth decay Weakened bones Kidney failure Liver disease Frankly, the list goes on and on. The earlier you get a smoking test done, the better it is.