There are an unlimited number of health reasons for giving up smoking. The risk of suffering for example from the following diseases decreases:

Cancer: lung cancer, mammary carcinoma, ovarian cancer, lip cancer, mouth cancer, throat cancer, oral ???, gullet cancer, pancreas cancer, kidney cancer, bladder cancer, colon cancer, prostate cancer, stomach cancer, liver cancer, leukaemia.
Acne and wrinkles.
Erection problems and impotence
Childlessness (both men and women), miscarriages
Menstrual disorders
Female facial hair
The mouth diseases: Periodontal disease, tartar, gingivitis
Osteoporosis
Chronic breathing infections, bronchitis, pulmonary emphysema, bronchial constriction
Coronary and vascular diseases, coronary thrombosis, cerebral thrombosis and cerebral haemorrhage, cardiac infarction, coronary artery disease, hypertension, stroke
Depression and insomnia
Erosion of spine and vertebral discs.