Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Cancer Health Center

Font Size

Marijuana Smoke Linked to Cancer

Scientists Say Marijuana Smoke Damages DNA
WebMD Health News
Reviewed by Louise Chang, MD

June 23, 2009 -- Smoking pot causes cell damage that could make a person more likely to develop cancer, researchers report.

Scientists at the University of Leicester have discovered that marijuana (cannabis) smoke alters DNA, the genetic material located in cells of the human body. Some forms of DNA damage can lead to cancer.

Many studies have shown that tobacco smoke damages DNA in a way that boosts risk for lung and other cancers, but until now, it's been unclear whether cannabis smoke could do the same. Of particular concern is a cancer-causing chemical called acetaldehyde, which is found in both tobacco and marijuana smoke. Using new chemistry techniques, study researchers showed that the chemical, when present in marijuana smoke, caused DNA damage in a laboratory setting.

The discovery suggests that marijuana smoke may be as harmful, or perhaps even more toxic, than tobacco smoke. In fact, study researchers say that smoking three to four marijuana cigarettes a day causes as much airway damage as smoking 20 or more cigarettes a day.

"These results provide evidence for the DNA-damaging potential of cannabis smoke," the researchers write, "implying that the consumption of cannabis cigarettes may be detrimental to human health with the possibility to initiate cancer development."

The findings appear in this month's issue of Chemical Research in Toxicology.

Today on WebMD

Colorectal cancer cells
New! I AM Not Cancer Facebook Group
Lung cancer xray
See it in pictures, plus read the facts.
sauteed cherry tomatoes
Fight cancer one plate at a time.
Ovarian cancer illustration
Real Cancer Perspectives
Jennifer Goodman Linn self-portrait
what is your cancer risk
colorectal cancer treatment advances
breast cancer overview slideshow
prostate cancer overview
lung cancer overview slideshow
ovarian cancer overview slideshow
Actor Michael Douglas