瘴气作为古代的疾病地理概念，主要与南方气候、植被和地貌有关。但大量历史文献记载的瘴气现象，却多数是对雾尘霾等天气现象的误解。历史上关于瘴的疾病问题也十分模糊，医学界往往以为过去之瘴即今之疟疾，而实际上广义的瘴病包括南方所有地方病和传染病，狭义的瘴病则指感冒、疟疾和中暑等症。瘴气之说在中国始于公元1世纪，自清代中叶后，随着南方地区的大规模经济开发而逐渐消失，其主要原因可归结为传统观念的转变和医学文化普及。此外，历代有关瘴气的许多文献记载，也涉及环境变迁和人类疾病谱诸方面的史料，这些历史信息在今天仍有很好的研究价值。

Miasma, as an old idea of disease geography, had much relationship with the climate, vegetable and landforms in the south of China. However, miasma phenomenon in most historical records was misunderstood as fog or haze and other weather phenomena. It was not so clear in the history on the idea of miasma disease which is regarded as malaria in the old days in medical circles. But as a matter of fact, miasma diseases in broad sense, include various endemic and infectious diseases in the south, while in limited sense include common cold, malaria and sunstroke etc, Theory of miasma began at the 1st century and gradually disappeared since the middle on Qing Dynasty with the large-scaled economic development in the south. It mainly resulted from the change of traditional idea and widely spread of medical knowledge. In addition, miasma is still related with environmental change and human disease category in some other historical records. Such information is still of much value in the present research.