The scientists said that 3-4 marijuana cigarettes PER DAY are equivalent to 20 tobacco cigarettes.

Who smokes 3-4 joints per day? That is a lot of weed and most users, even daily users, probably smoke less than 1 marijuana cigarette daily. Maybe a person with a very serious disease or a chronic pot-head would smoke that much every day, but most cannabis users smoke way less. Also, marijuana is much more powerful today, requiring the smoker to use substantially less pot to produce the desired effect.

Smoking marijuana is not the only delivery system into the body. There are machines now, Vaporizers, which heat the herb to a temperature that is just hot enough to release the active, beneficial "cannabinoids" without burning it and releasing the harmful, carcinogenic, DNA altering chemicals. Cannabis can also be cooked into foods and eaten or prepared into concentrated oil and used as a tincture. Cannabis can be taken safely by other means than smoking.

Anything taken in excess can be detrimental to the body. Too much wine or beer, too much fat, too much sugar, too much aspirin, can all be harmful if "abused", but are beneficial and actually healthy when used in moderation.

If cannabis is smoked in moderation, how much does that reduce the risk?

A University of California researcher who has performed US-government sponsored studies of marijuana and lung function for over 30 years says that pot should be legal.

In an interview with the McClatchy newspaper chain, Donald Tashkin of the UCLA David Geffen School of Medicine, Division of Pulmonary and Critical Care Medicine, said: "[A]t this point, I'd be in favor of (marijuana) legalization. I wouldn't encourage anybody to smoke any substances. But I don't think it should be stigmatized as an illegal substance. Tobacco smoking causes far more harm. And in terms of an intoxicant, alcohol causes far more harm (than marijuana)."

Tashkin said that when he began his work thirty years ago, he "opposed ... legalization because [he] thought it would lead to increased use and that would lead to increased health effects." However, he now admits that his decades' worth of scientific research revealed an opposite conclusion.

In 2006, Tashkin led the largest population case-control study ever to assess the use of marijuana and lung cancer risk. The study, which included more than 2,200 subjects (1,212 cases and 1,040 controls), reported that marijuana smoking was not positively associated with cancers of the lung or upper aerodigestive tract – even among individuals who reported smoking more than 22,000 joints during their lifetime.

Ok, definitly watch 'the union' totally different story! People are always trying to find stuff against cronic because of the fact that it actually helps u in many ways. Ppl r so clueless! 1st of all, we live in 2009, almost 2010, they aren't called marijuana cigarettes anymore! Call them joints, or splifs. And I duno what world the 1st comment lives in, but actual pot heads do smoke from 2-4 joints a day! And that's speaking from every day, day to day life experiences. Smoking cigarettes, drinking alcohol, its all worse than smoking weed! You only live once, so stop focussing so hard on making weed seem worse than it is!
Its a plant! Don't panic! Its organic!