Hand-foot-mouth disease belongs to the category of “pestilence ”of epidemic febrile disease of TCM, caused by the warm-wet disease virus infection. Severe hand-foot-mouth disease develops from the common type, locating in lung, spleen, and heart, liver, following the defensive-qi-nutrient-blood development principle of TCM. It begins with lung Wei, and develops to qifen period，then moves to yin and blood period in critical period when heat evil invaginates liver and pericardium, and intense heat generates wind, then symptoms of high fever, clouded spirit, seizure, rigidity of the neck and nape would been seen; if heat evil invaginates heart and lung，the lungs would lose its clearing action，then fluid stops in the body and attacks the heart, then symptoms of palpitation, frequent coughing and rapid breathing, lip cyanosis, change of breath rhythms would be seen; if pathogenic heat burns pulmonary vessels, then blood overflows to outside of pulse, or Qi –yin is damaged by pathogenic heat, and Qi fails to control blood, the symptoms of cough, spitting white or pink frothy sputum will be observed; if disease develops and damages yang, then severe and critical syndrome as internal obstruction and external collapse will be seen including symptoms of high fever, clouded spirit, pale expression, severe sweating, counterflow cold of the limbs.