Summer-heat is transformed "from heat and fire in summer. Summer-heat pertains to yang and usually appears after summer solstice and before autumn solstice. The attack by summer-heat is either due to hot weather or due to low adaptability of the body to the environment.

Summer-heat is characterized by the following features:

Summer-heat pertains to yang and is hot in nature. So the disease caused by summer-heat is usually marked by a series of yang symptoms such as high fever, dysphoria, reddish complexion, thirst with preference for cold drink and full and large pulse, etc.

    

Summer-heat pertains to yang and tends to disperse and elevate. Summer-heat disturbs the mind when it elevates, leading to dysphoria and dizziness or even sudden coma and unconsciousness in severe cases. Summer-heat induces sweating and consumes body fluid when it disperses, leading to thirst with preference for drinking water and reddish and scanty urine. If there is profuse sweating, qi will get lost, eventually bringing on shortness of breath and lassitude due to qi deficiency.

     

In the hot season, heat fumigates dampness. That is why dampness is exuberant in summer and often mixes up with heat to attack people. Thus disease caused by summer-heat-dampness is often, apart from fever and extreme thirst, characterized by lassitude of the four limbs, chest oppression, vomiting and unsmooth loose stool, etc.