國人十大死因大都和吸菸有關，包含癌症、心臟病、中風及慢性肺部疾病等。每年至少有2萬人死於菸害，平均每25分鐘就有1人因菸害而失去生命。美國癌症協會(ACS) 2013的菸草與健康圖鑑《Tobacco Atlas》表示，全球8億男性吸菸者中，約20%來自高收入國家，80%以上在中低收入國家；約2億女性有吸菸的習慣，其中50%來自高收入國家；50%在中低收入國家。在全球中，男性約80%的肺癌死亡和女性約50%的肺癌死亡是由吸菸導致的。
根據世界衛生組織統計，2013年發表的非傳染性疾病各國概況顯示，全球非傳染疾病為世界最大死因，約有63%的死亡是由非傳染性疾病所引起的，多數非傳染病是可預防的，而吸菸是引起全球死亡之危險因子最主要的風險因素，因而預防或控制菸品成為全球首要的可預防死亡之措施。從2002年以來，菸害導致全球死亡人數增長近3倍，每年全球平均已有600萬人死於菸害，平均每5.3秒即有1人死於菸害，使用菸品者平均壽命減少約15年，若菸害未能加以控制，至2030年，每年將有800萬人死於吸菸相關疾病，吸菸已於20世紀讓1億人失去生命，21世紀將奪去10億人的生命。事實上，吸菸幾乎傷害身體的每個器官，即使不直接造成死亡，對於吸菸者的生活品質也多少會有影響，例如：呼吸困難、工作不便等。
吸菸更是致癌的主因之一，菸草中含有超過7,000種化學物質和化合物，其中數百種是有毒的，至少有93種已知的致癌物，世界衛生組織指出，菸、酒、不健康飲食、缺乏身體活動及肥胖等主要危險因子，佔癌症死因的30％。佔國人罹癌排行榜加總6成左右的大腸癌、肝癌、肺癌、乳癌及口腔癌等五種癌症，都與前述致癌因子有關。如：肺癌的發生受到吸菸與二手菸的影響甚大，口腔癌及食道癌與抽菸、喝酒、嚼檳榔息息相關。
至少有22％的癌症由菸害造成，世界衛生組織指出，與吸菸者同住，得到肺癌的機會比一般民眾高出20%-30%，長期二手菸暴露更會造成或加重孩童呼吸道疾病，且與兒童白血病、淋巴瘤、大腦與中樞神經系統病變、肝母細胞瘤等癌症有關。菸草內主要引致癌症的物質來自焦油，可能直接引發的癌症包括肺癌、口腔癌、咽頭癌、喉頭癌、膀胱癌、食道癌，而間接可引發的癌症包含頸癌、血癌 (骨髓性白血病)、胃癌、肝癌、腎臟癌、胰臟癌、大腸癌、子宮頸癌等。
Tobacco Hazard to Human Body
Most of the top ten leading causes of death including cancer, heart disease, stroke, and chronic pulmonary disease, etc. in Taiwan are associated with smoking. At least 20,000 people have died from tobacco hazard annually, suggesting that 1 person has lost his/her life to tobacco hazard every 25 minutes on average. The《Tobacco Atlas》published by the American Cancer Society (ACS) at 2013 indicated that among the 800 million male smokers worldwide, approximately 20% of them were from high-income countries, and the rest 80% were from medium-to-low income countries; While in about the 200 million female smokers, 50% of them were from high-income countries and the other 50% were from medium-to-low income countries. According to the global statistics, approximately 80% of lung cancer mortality in males and 50% in females were caused by smoking.
According to the World Health Organization (WHO) statistics in 2013, the global overview of non-communicable disease (NCD) distribution demonstrated that NCD has become the top leading cause of death worldwide and about 63% of death was associated with NCD. Fortunately, most of the NCDs are preventable. As smoking is the primary risk factor contributing to NCD death worldwide, tobacco hazard prevention and control has become the prioritized preventive measures of death. Starting from 2002, the number of global death caused by tobacco hazards has increased almost 3 folds, suggesting that averagely 6 million people have died of tobacco hazards worldwide in each year (i.e. 1 has died of tobacco hazards every 5.3 second), and the average life among tobacco users has decreased by approximately 15 years. If the tobacco hazard failed to be confined, 8 million people will die of smoking-related diseases annually by 2030. In fact, smoking has resulted in 100 million deaths in 20th century and expected 1 billion deaths in 21st century. In reality, smoking almost harms to every organ in the body. Even it may not result in death directly, smoking definitely has somewhat negative impacts on the quality of life (QOL) to the smokers. (e.g. short of breath, inconvenience at work, etc.)
Smoking is one of the main carcinogenic factors, tobacco consists of more than 7,000 chemicals and compounds. Hundreds of them are toxic and at least 93 components are known carcinogens. According to WHO, primary risk factors such as tobacco, alcohol, unhealthy diet, sedentary lifestyle and obesity have accounted for 30% of cancer mortality. About 60% of top five leading cancers in Taiwan (i.e. colorectal cancer, liver cancer, lung cancer, breast cancer and oral cancer) are associated with the aforementioned carcinogens. For example, tobacco use and secondhand smoke are major contributors to lung cancer, where smoking, drinking and betel nuts chewing are closely associated with oral and esophageal cancers.
At least 22% of cancers were caused by tobacco hazards. WHO has indicated that the incidence of lung cancer among people cohabiting with tobacco users were 20%-30% higher than that of general public. Moreover, long-term secondhand smoke exposure not only results in or aggravates the respiratory diseases in children, but also is closely associated with pediatric leukemia, lymphoma, brain-central nervous system lesions, and hepatoblastoma, etc. The primary carcinogenic component in tobacco is tar, which may contribute to lung cancer, oral cancer, laryngeal cancer, pharyngeal cancer, bladder cancer and esophageal cancer directly, and result in neck cancer, leukemia (myeloid leukemia), gastric cancer, liver cancer, renal cancer, pancreatic cancer, colorectal cancer, and cervical cancer etc. indirectly.