While it is true that marijuana has more carcinogens than tobacco, there appears to be something in the cannabanoids which helps protect against the carcinogens. People also smoke less pot than tobacco and marijuana smoke doesn't block the small airways in the lungs like tobacco does.

A great piece on marijuana myths can be found here...

Myths and Facts About Marijuana


Myth: Marijuana is More Damaging to the Lungs Than Tobacco. Marijuana smokers are at a high risk of developing lung cancer, bronchitis, and emphysema.

Fact: Moderate smoking of marijuana appears to pose minimal danger to the lungs. Like tobacco smoke, marijuana smoke contains a number of irritants and carcinogens. But marijuana users typically smoke much less often than tobacco smokers, and over time, inhale much less smoke. As a result, the risk of serious lung damage should be lower in marijuana smokers. There have been no reports of lung cancer related solely to marijuana, and in a large study presented to the American Thoracic Society in 2006, even heavy users of smoked marijuana were found not to have any increased risk of lung cancer. Unlike heavy tobacco smokers, heavy marijuana smokers exhibit no obstruction of the lung's small airway. That indicates that people will not develop emphysema from smoking marijuana.

*
Center on Addiction and Substance Abuse. “Legalization: Panacea or Pandora’s Box.” New York. (1995): 36.

*
Turner, Carlton E. The Marijuana Controversy. Rockville: American Council for Drug Education, 1981.

*
Nahas, Gabriel G. and Nicholas A. Pace. Letter. “Marijuana as Chemotherapy Aid Poses Hazards.” New York Times 4 December 1993: A20.

*
Inaba, Darryl S. and William E. Cohen. Uppers, Downers, All-Arounders: Physical and Mental Effects of Psychoactive Drugs. 2nd ed. Ashland: CNS Productions, 1995. 174.

///////

Myth: Marijuana's Harms Have Been Proved Scientifically. In the 1960s and 1970s, many people believed that marijuana was harmless. Today we know that marijuana is much more dangerous than previously believed.

Fact: In 1972, after reviewing the scientific evidence, the National Commission on Marihuana and Drug Abuse concluded that while marijuana was not entirely safe, its dangers had been grossly overstated. Since then, researchers have conducted thousands of studies of humans, animals, and cell cultures. None reveal any findings dramatically different from those described by the National Commission in 1972. In 1995, based on thirty years of scientific research editors of the British medical journal Lancet concluded that "the smoking of cannabis, even long term, is not harmful to health."

*
United States. National Commission on Marihuana and Drug Abuse. Marihuana: A signal of misunderstanding. Shafer Commission Report. Washington, D.C.: U.S. Government Printing Office, 1972.

*
“Deglamorising Cannabis.” Editorial. The Lancet 356:11(1995): 1241.

////////

I have seen one study which showed that HEAVY use of marijuana can lead to bronchitis, but that is the only severe health effect I have seen from a respected study.

Now, the WHITEHOUSE has their own MYTHS ABOUT MARIJUANA PAGE.

Here is one part.

http://www.whitehousedrugpolicy.gov/...acts/myth1.pdf

This piece mentions how marijuana can affect learning, memory, can lead to anxiety, panic attacks and depression, as well as "other" mental disorders.

While I believe there is "some" truth to this, in my opinion, marijuana is more often used to self medicate people who already have these problems and is not the cause of such problems. There are always exceptions to every rule, but if marijuana was half as dangerous as the government tells us, we would have major problems in this country from marijuana users, since there are millions of them.

In the next piece from the Whitehouse on marijuana and health, they claim that marijuana decreases lung function, but they don't mention cancer, emphyzema, or any particular diseases.

If you look at the piece I posted on Marijuana myths and then compare it to the Whitehouse list, it shows how much of a joke the Whitehouse list is.

The piece from DRUG POLICY actually lists studies and links to references, whereas the Whitehouse piece only mentions a few studies.

Another great MYTH page...

Marijuana Health Mythology

A GOVERNMENT STUDY FROM CANADA.....

Marijuana is a not a serious health risk. "Cannabis may have some negative effects on the health of individuals, but considering the patterns of use, these effects are relatively benign."

Senate Special Committee on Illegal Drugs - S


More....

In fact, the oldest continuously published pediatric journal in the country, a Journal of the American Medical Association called the "Archives of Pediatrics & Adolescent Medicine", released new information in November '07 (see: Study Shows Surprisingly Few Negative Impacts on Kids Who Use Marijuana) indicating that pot smoking teens tend to function at better levels than teens who also smoke tobacco, and better in some ways than kids who abstain from both.

New Federal Report on Marijuana Use is Misleading, Groups Say - Salem-News.Com

Study after study show that marijuana is not even close to as harmful as we have been told for the last 80 years.

Most of what the government told us has been proven false, even though the government made it very difficult to even do marijuana research.

If you do your own research, I think everyone here will find that almost everything the government has told us about marijuana is a LIE.

IF you do your own research, it is important to NOT neglect the Reefer Madness campaign from the 1930s.

"Marihuana more dangerous than heroin or cocain" - By H. J. Anslinger - May 1938

Here is a collection of articles which can be looked up, if one wishes....

Pulp Fiction Magazines / reefer madness / anti- medical marijuana <META NAME="KEYWORDS" CONTENT="museum,hemp,marijuana,marihuana, Reefer Madness,harry j Anslinger,Federal Narcotic Bureau,pulp fiction magazines,True detective, true crime, american his

A few examples of quotes........

1910: “Marihuana is the most frightening and vicious drug ever to hit New Orleans.” —New Orleans Public Safety Commission

1920s: “Makes darkies think they’re as good as white men.” —H.J. Anslinger, Bureau of Narcotics

1930: “Marihuana is responsible for the raping of white women by crazed negroes.” —Hearst Newspapers Nationwide

1932: “Hasheesh goads users to blood lust.” —Hearst Newspapers

1935: “Marihuana influenced negroes to look at white people in the eye, step on white men’s shadows, and look at a white woman twice.” —Hearst Newspapers

1937: “Marihuana is the most violent drug in the history of mankind.” —Congressional Testimony, H.J. Anslinger, FBN

1938: “Marihuana is more dangerous than heroin or cocaine.” —Anslinger, Scientific American, May, 1938

1938: “If the hideous monster of Frankenstein came face to face with marihuana, he would drop dead of fright.” —Anslinger, FBN, quoted in Hearst newspaper

Appendix — Historical

NOW, thinking people might ask themselves, why were such OUTRAGEOUS LIES told about marijuana?