Summer-Heat Summer-Heat

Summer-Heat  is one of the six exterior pathogens (i.e. a quality in the environment or climate which can cause disease). It is the predominant climatic factor in summer and arises from the transformation of heat and fire. It is also a pure exogenous (external) pathogen, and there is no equivalent endogenous (internal) pathogen. As its name suggests, it is a condition usually arising from excessive heat in summertime, i.e. a heatwave. An attack by Summer-Heat can also be due to low adaptability of the body to the environment. It often combines with Dampness to manifest as certain types of illness.


  • Pure Yang pathogenic factor characterised by burning heat
  • Tendency to injure Yin
  • Associated with the Heart

Symptoms and Signs:

The invasion of the body by Summer-Heat often manfiests with the following clinical symptoms.

  • High fever
  • Profuse sweating
  • Aversion to heat
  • Thirst with a strong desire to drink
  • Headaches
  • Restlessness
  • Dry lips
  • Dizziness and blurred vision
  • Flushed face
  • Scanty yellow urine and constipation
  • Collapse of Yin
  • Dry, red tongue and a surging pulse.
  • In severe cases it may result in delerium, slurred speech or unconsciousness.

If it combines with Dampness, the Heat will cause the Damp to transform to Phlegm and it will manifest with the following symptoms.