Defensive phase syndrome refers to the syndrome due to invasion of pathogenic factors into the lung, disorder of defensive qi and dysfunction of the lung. This syndrome is usually seen at the primary stage of epidemic febrile disease.
 
Clinical manifestations:
Fever, slight aversion to cold and wind, reddish tongue tip, whitish thin or slightly yellow tongue fur, floating and rapid pulse, usually accompanied by headache, cough, dry mouth, slight thirst and swelling pain of the throat.
 
Analysis of the symptoms:
Fever and slight aversion to cold and wind are caused by struggle between pathogenic factors and defensive qi in the superficies; headache is due to febrile pathogenic factors disturbing the head; cough is due to febrile pathogenic factors attacking the lung; slight thirst and dry mouth are due to mild consumption of body fluid at the primary stage of epidemic febrile disease; swelling and painful throat are due to febrile pathogenic factors attacking the lung, scorching the throat and stagnation of qi and blood; reddish tongue tip, whitish thin or slightly yellow tongue fur, floating and rapid pulse are the signs of febrile pathogenic factors invading the superficies.