Tobacco smoking is the inhalation of smoke from burned dried or cured leaves of the tobacco plant, most often in the form of a cigarette. People smoke for pleasure, to satisfy a nicotine addiction, for ritualistic or social purposes, or for self-medication, . Tobacco use by Native Americans throughout North and South America dates back to 2000BC. The practice was brought back to Europe by the crew of Christopher Columbus. Tobacco smoking took hold in Spain and was introduced to the rest of the world, via trade. Tobacco is an agricultural product processed from the fresh leaves of plants in the genus Nicotiana. Tobacco has been growing on the northern continents since about 6000 BC and began being used by native cultures at about 3000 BC. It has been smoked in one form or another since about 2000 BC. There are pictoral drawings of ancient Mayans smoking crude cigars from 1400 BC.

Tobacco smoke contains nicotine and harmane (a MAO inhibitor), which combined give rise to addictive stimulant and euphoriant properties. The effect of nicotine in first time or irregular users is an increase in alertness and memory, and mild euphoria. Nicotine also disturbs metabolism and suppresses appetite. This is because nicotine, like many stimulants, increases blood sugar levels.

Medical research has determined that chronic tobacco smoking can lead to many health problems, particularly lung cancer, emphysema, and cardiovascular disease. Tobacco smoking killed 100 million people worldwide in the 20th century and could kill 1 billion people around the world in the 21st century, the WHO Report warned.