The six qi (liuqi) refers to an ancient Chinese concept still relied upon in today’s discussions of traditional Chinese medical practices. The concept behind the term is that external (environmental) conditions can influence the functions of the body. When the environmental conditions are moderate and normal (e.g., “seasonable weather”) and the person is dressed properly and protected from over exposure, the sixqi have a positive influence. However, when the conditions become extreme, when they change rapidly, or when they do not follow the usual pattern, they are able to adversely affect health, and cause disease. In such cases, the six qi are known as liuyin (six excesses) or even liuxie (six evils).
By Ziegler175 (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons