Cigarettes and marijuana both can damage the lung. In reality, cigarettes probably damage more tissue simply because most people smoke many more cigarettes than they do marijuana. If someone smoked a "pack or two" of marijuana cigarettes every day, like cigarette smokers often do with cigarettes, they would probably end up with a similar degree of damage to their lungs. It is also important to realize that cigarettes are not just paper and tobacco but also many chemical additives so that they burn "properly." Marijuana tends not to contain these chemical additives, but may contain other equally damaging substances placed intentionally or inadvertently in the drug.