Cigarettes like other tobacco products, do carry serious health effects with them. Nicotine, the primary psychoactive chemical in tobacco and therefore cigarettes, is addictive. About half of cigarette smokers die of tobacco-related disease and lose on average 14 years of life.Cigarette use by pregnant women has also been shown to cause birth defects, including mental and physical disabilities. Second-hand smoke from cigarettes has also been shown to be injurious to bystanders.