Tobacco and alcohol contain harmful substances such as methanol, cyanide, nicotine, tar, carbon monoxide, formaldehyde and other irritants. If you drink and smoke for a long time, it can damage your oral cavity, injure your liver, and you may also have sexual dysfunction. 1. Damage to the oral cavity: drinking and smoking may cause oral cancer. Long-term smoking and drinking will cause inflammation of salivary glands and decrease the ability of taste and smell, which will easily lead to oral cancer. 2. Damage to liver: Cigarettes contain carbon monoxide, which will reduce the ability of blood to absorb oxygen. Drinking alcohol will have some effect on fat metabolism and even kill liver cells, which will do great harm to the liver, and if you smoke and drink for a long period of time without moderation, you will have the possibility of developing cirrhosis of the liver. 3. Sexual dysfunction: nicotine contained in cigarettes, and alcohol will also affect the male sexual function, can reduce the sperm vitality and reduce the number of sperm, nicotine in tobacco and alcohol, plasticizers, phthalates and other harmful substances will have a certain impact on blood circulation, will make the genital blood flow decrease, thus triggering male sexual dysfunction. Smoking and alcohol abuse will bring great harm to men’s health, will cause a lot of diseases, but also induce the occurrence of some cancers. So it is recommended that men stop smoking and drinking.