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Tar in Cigarettes

The Toxic Chemicals in Cigarettes


Updated May 16, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Tar in Cigarettes

Tar in Cigarette Butts

Sami Sarkis/Photographer's Choice RF/Getty Images

"Tar" is the term used to describe the toxic chemical residue left behind from burning cigarettes.

The concentration of tar in a cigarette determines its rating:

  • High-tar cigarettes contain at least 22 milligrams (mg) of tar
  • Medium-tar cigarettes from 15 mg to 21 mg
  • Low-tar cigarettes 7 mg or less of tar
Cigarette filters were first added to cigarettes in the 1950s when it was reported that the tar in cigarettes was associated with an increased risk of lung cancer. The idea was that the filter would trap harmful tars and nicotine, but the design never worked as well as hoped. Toxins still make it through and into the smoker's lungs, exposing them to the risks of smoking-related disease.

In solid form, tar is also known as third-hand smoke.  It is the brown, tacky substance left behind on the end of the cigarette filter. It stains a smoker's teeth and fingers brown and coats everything it touches with a brownish-yellow film.  Imagine that settling into the delicate pink tissue of your lungs.

Tar is present in all cigarettes and tends to increase as the cigarette is burnt down, which can mean that the last puffs on a cigarette may contain as much as twice the amount of tar as the first puffs.

Tar in cigarette smoke paralyzes the cilia in the lungs, and contributes to lung diseases such as emphysema, chronic bronchitis, and lung cancer.

See also:
Are Light Cigarettes Less of a Risk for Smokers?


"Up In Smoke: The Truth About Tar and Nicotine Ratings" May, 2000. The U.S. Federal Trade Commission.

"A Vision for the Future." Surgeon General's Report 1981 Section 8. Centers for Disease Control.

"Low-Tar Cigarettes Do Not Cut Cancer Risk." 14 January, 2004. MIT News Office.

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