Within the framework of the Six Stages theory, this is one of the two patterns of the Bright Yang stage (the second of the six stages). Within the Four Levels theory, this is one of the five patterns of the Qi level (the second of the four levels).

It corresponds to a penetration of an External Pathogen to the level of the Stomach channel. No matter the original nature of the pathogen, be it Wind-Heat or Wind-Cold, this pattern is now resolutely characterized by Heat. As such the main characteristic symptom is high fever without chills.

Other Heat-related symptoms include a preference for cold drinks and food, tendency to less clothing irrespective of weather conditions, extreme thirst and excessive perspiration.