smoking - Tobacco smoking, often referred to as 'smoking', is the act of burning the dried or cured leaves of the tobacco plant and inhaling the smoke for pleasure or ritualistic purposes, or more commonly out of habit and to satisfy addiction. The practice was common among Native Americans of The Plains Indian religion, and was later introduced to the rest of the world by sailors following European exploration of the Americas. Tobacco smoke contains nicotine, an addictive stimulant which temporarily improves alertness and memory, but also forms a strong physical and psychological chemical dependence (addiction). Medical research has determined that smoking is a major contributing factor towards many health problems, particularly lung cancer (which has a survival percentage of 16.4%), emphysema, and cardiovascular disease.[1][2] Many countries regulate or restrict tobacco sales and advertising and require warnings be placed prominently on the product packaging. Many governments now ban smoking in a variety of public venues due to health impacts on non-smokers breathing second-hand smoke.