Smokers are often addicted to smoking, which is mainly the result of the long-term effects of nicotine. Nicotine, like other narcotics, is not adaptable when first smoked and can cause chest tightness, nausea, dizziness and other discomfort, but if you smoke for a long time, the nicotine in the blood reaches a certain concentration, repeatedly stimulating the brain and making the organs produce dependence on nicotine, at which point the addiction is wrapped up. Nicotine in tobacco is a neurotoxin, mainly against the human nervous system. Some smokers subjectively feel that smoking can relieve fatigue and invigorate the spirit, which is a momentary excitement of the nervous system, but in fact is the euphoria caused by nicotine. The nervous system is then inhibited after the excitement. Therefore, the sensitivity and accuracy of neuromuscular responses are reduced after smoking. The results of a study conducted by a foreign psychological research institute showed that the intellectual performance of smokers was 10 or 6% lower than that of nonsmokers. The common dangers of smoking Smoking is the most common cause of acute and chronic bronchitis, emphysema, tissue hypoxia, and lung cancer. Smoking is also associated with atherosclerosis, coronary heart disease, myocardial infarction, stroke, gastroduodenal ulcer, oral cancer, esophageal cancer, and bladder cancer. Smoking can block the microvasculature of the penile corpus cavernosum, causing the erection and lasting ability of men to be affected, causing premature ejaculation and impotence. The effect of smoking on fertility and offspring Smoking men have a reduced number of normal sperm, a significantly higher number of deformed sperm, reduced sperm motility, and sperm receiving tobacco carcinogens in body fluids, making them susceptible to genetic damage. More than 5,000 pregnant women have been analyzed and found that husbands who smoked more than 10 cigarettes a day had greatly increased prenatal fetal mortality. The proportion of women whose husbands smoked who gave birth to defective children was about 2 or 5 times higher than those whose husbands did not smoke. American Dr. Kareno in order to clarify the health risks of tobacco at the chromosomal level, he conducted chromosomal observation of different groups of smokers, the results found that in normal people 46 chromosomes in general only 7-10 abnormalities, while smokers can be up to about 20 chromosomes sister monosomal interchange. The longer the smoking history and the greater the amount of smoking, the higher the rate of chromosomal abnormalities. The effects of smoking persist even after 3 months of stopping smoking. In addition, the percentage of cells with chromosomal abnormalities is 70% in smokers and only about 15% in nonsmokers. In women who smoked more than 10 cigarettes a day, the infertility rate was 10.7% after stopping the use of contraception. The infertility rate for nonsmokers was only 5.4%. Women who smoke during pregnancy have an increased incidence of placental abruption, placental infarction and placenta praevia, a high incidence of preterm births, an increased incidence of miscarriage, and a high incidence of congenital malformations. Couples preparing for pregnancy should quit smoking for at least three months and avoid “second-hand smoke”.