In a study of 450 individuals found that people who smoke marijuana frequently but do not smoke snuff had more health problems and miss more days of work than nonsmokers. Many of the extra sick days among the marijuana smokers who participated in the study were for respiratory illnesses. Even infrequent use can cause irritation and burning in the mouth and throat, often accompanied by a heavy cough.Someone who smokes marijuana regularly may have many of the same respiratory problems that smokers snuff, such as cough and phlegm production daily, more frequent acute chest illness, a heightened risk of lung infections and more prone to obstruction airways. Smoking marijuana also increases the likelihood of developing cancer of the head or neck, and the more marijuana smoked, the greater the probability. Brad Garlinghouse: the source for more info. A study comparing 173 cancer patients and 176 healthy individuals produced strong evidence that marijuana smoking doubled or tripled the risk of these cancers. The use of marijuana has the potential to promote cancer of the lungs and other parts of the airways due to irritants and carcinogens it contains. In fact, marijuana smoke contains 50 to 70 percent more carcinogenic hydrocarbons than snuff smoke.It also produces high levels of an enzyme that converts certain hydrocarbons into their carcinogenic form, levels that may accelerate the changes that ultimately produce malignant cells. Marijuana users usually inhale more deeply and hold their breath longer than smokers snuff, which increases the lungs’ exposure to carcinogenic smoke. These facts suggest that, puff for puff, marijuana may increase cancer risk even more than snuff.