Me with this. i need to saw this information in my own words.
a single puff of tobacco smoke contains more than 4,000 chemicals. almost all of these chemicals prevent the body from functioning the way it should. at least 43 of them cause cancer in smokers. in the united states more than 400,000 people die each year as a result of smoking-related illnesses. smoke also harms the health of nonsmokers. even smokeless tobacco causes health problems for its users.
tobacco contains three substances that are especially harmful to health. nicotine ( nik-uh-teen) is an addictive drug found in tobacco. nicotine makes tobacco users crave even more nicotine. tar is a thick, dark liquid that forms when tobacco burns. this liquid coats the lining of the lungs and causes diseases. carbon monoxide (kar-buhn muh-nahk-syd) is a colorless, odorless, poisonous gas produced when tobacco burns. tobacco smoke from a cigarette, cigar, or pipe contain all of these substances.
tobacco has harmful effects on almost all body systems. tobacco smoke damages the alveoli (al-vee-oh-ly), fragile, elastic, microscopic air sacs in the lungs where carbon dioxide from the air are exchanged. this damage may lead to emphysema (em-fuh-zee-muh), a disease that destroys alveoli.
all forms of tobacco increase the risk of cavities and gum disease. tobacco dulls the taste buds and can cause stomach ulcers. tobacco use is linked to cancer of the mouth, throat, esophagus, stomach, and pancreas. it is also linked to heart disease.
tobacco use reduces the flow of oxygen to the brain, which can lead to a stroke. smokers have at twice the risk of developing bladder cancer as nonsmokers. smokeless tobacco can also put users at risk of developing bladder cancer.

Stop! Stop and put that cigarette down! One blow of the smoke can contain more 4,000 harmful chemicals. Smoking can cause cancer, more than 400,000 people died because of smoking and having cancer in the United Staes. When you blow these 4,000 harmful chemicals, they go into your body and take over and your body wouldn't be the same as before like it won't function normally. Tobacco has three substances that are harmful to your body. One of the substance is Nicotine, Nicotine is a tar that is thick and dark, it kinda looks like when your burning coals. It has this dark liquid around the tobacco after when the cigarette is burned. This liquid coat can be harmful to your lungs and can cause diseases. Nicotine is an addictive drug that makes you want more of its Nicotine. Another substance would be Carbon monoxide, carbon monoxide is poisonous gas when you light up your cigarette, also Carbon monoxide doesn't have a smell or a color. Whatever you smoke on, from cigarettes to pipe, it still has this harmful effect toward your body. Tabacco damages alveoli, elastic, fragile, microspofic air sacs in you lungs where the carbon dioxide is exchanged. When you smoke cigarettes (whatever it is that you smoke with), you are highly likely to get gum disease and cancer. Smoking makes you taste bud dull, like you can't taste food, and which can cause stomach ulcer. Stomach ulcer is when the stomach acid damage your digestive tract  (like the lining part). Tobacco is linked to cancer of your mouth to your throat to your esophagus to your stomach and to your pancrease, and that is also linked to heart disease. Tobacco can let the flow of oxygen into your brain less than usually, which having having less oxygen in your brain can lead to stroke. Smokers have a high chance of developing bladder cancer than nonsmokers and bladder cancer is a cancer that start off to your bladder. Even smokeless tobacco  can put you in risk of bladder cancer. Even if you don't smoke, well good for you, but be careful dont breath in the smoke that smokers have smoke because you still have a chance to develop cancer and other diseases. If you want to avoid the smoke from the smoker, then just hold your breath before and do not smell of breath in the smoke! Also just walk away quickly or run if you like but still hold your breath! So you heard all the scary, and negative things about smoking and if your wondering, well where's the good thing about smoking? . . . THERE IS NO GOOD THING ABOUT SMOKING :)