Smoking is the act of inhaling smoke, produced by the combustion of an element, through the mouth, usually of tobacco in a cigarette, cigar, or pipe. Smoking often, especially cigarettes, which contain many toxic substances such as nicotine or tar, is a proven health hazard. This results in different diseases, including those that are respiratory and cardiac in nature, which can lead to the death of the smoker. Smoking is a habit difficult to break because the nicotine in tobacco creates a chemical dependency, but today there are various methods for quitting: therapy, nicotine replacement ... Quitting smoking is beneficial at all levels. Some other toxic substances can be smoked, such as marijuana.