The harmful effects of smoking include lowering immunity, damaging the respiratory system or triggering cardiovascular diseases. 1. Lower immunity: nicotine and tobacco oil and other harmful substances into the body, will contribute to the body’s immunity to decline, accelerate the aging of the skin. 2. Damage to the respiratory system: the tar component of tobacco toxic gases and particles enter the lungs with smoking, damaging the lungs. It can cause pneumonia, bronchitis, emphysema and other diseases, and serious risk of lung cancer. 3. Trigger cardiovascular disease: Smoking can lead to poor blood circulation in the body, reducing the content of high-density lipoprotein. This increases the risk of cardiovascular diseases such as heart disease, aneurysm or sudden death. 4. Smoking by pregnant women can also lead to serious consequences such as poor fetal development or chromosomal abnormalities. Smoking can also make a person’s sense of smell, taste and other organs sluggish, dementia occurs earlier, smoking will also damage oral health, aggravate vision loss, cause bone decalcification, deformation, brittle, easy to fracture and so on. Quitting smoking is good for physical and mental health, so stay away from cigarettes.