Merck Manual

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Quick Facts



The Manual's Editorial Staff

Last full review/revision Sep 2019| Content last modified Sep 2019
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Why is smoking tobacco bad for my health?

People smoke tobacco in cigarettes, cigars, and pipes. Tobacco smoke has many harmful chemicals that cause problems in your whole body, not just your lungs.

Breathing in smoke from someone else who is smoking, called second-hand smoke, can cause the same health problems as smoking yourself.

Smoking while pregnant can hurt the unborn baby and cause:

What about e-cigarettes?

Electronic cigarettes, called e-cigarettes, contain liquid nicotine and flavored chemicals, not tobacco. The e-cigarette heats the liquid into a vapor that you breathe in.

  • You can become addicted to e-cigarettes because they contain nicotine and nicotine is addictive

  • Because nothing burns in an e-cigarette, you don't get the problems caused by smoke

  • E-cigarettes haven't been around long enough for doctors to know the long-term risks

What if a child swallows nicotine?

A child who has eaten a cigarette or anything with nicotine (such as nicotine gum) needs emergency treatment. Doctors will treat the child for nicotine poisoning.

What are the effects of smoking?

Immediate effects

You often don't feel anything from smoking, but you may feel:

  • More energy

  • Better able to concentrate

  • Less hungry

If you try smoking and aren't used to it yet, you may feel sick to your stomach, flushed, or both.

Long-term effects

Smoking hurts nearly every organ in your body. The main smoking-related problems are:

Smoking also makes it more likely you will have:

Smoking also causes:

  • Dry and wrinkled skin

  • Thinning hair

  • Yellow teeth

  • Weight loss

Withdrawal symptoms

If you quit smoking, you may go through withdrawal. Withdrawal is when you feel sick after you stop taking a drug that you took for a long time. Smoking withdrawal can cause you to:

  • Want to smoke

  • Feel moody, anxious, sleepy, or sad

  • Have headaches and trouble concentrating

  • Tremble (tremor)

  • Have an upset stomach and gain weight

Should I talk to my doctor about my smoking?

Yes, you should talk to your doctor about smoking and how much you smoke.

Your doctor can:

  • Explain why smoking can harm your body

  • Help you quit smoking

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