Cold and flu mostly belong to the wind-cold cold, which is a clinical symptom of the wind-cold evil attacking the body’s muscle surface and lung health. We should use drugs that relieve the symptoms and clear heat. Commonly used formulas are Ephedra Tang and Gui Zhi Tang. Ma Huang Tang is composed of Ephedra, Gui Zhi, Almond, and Roasted Licorice. It is mainly used for the symptom of exogenous wind-cold manifestations. The clinical manifestations are vicious cold and fever, head and body pain, wheezing without sweating, thin white tongue coating, and floating and tight pulse. The main effects are to induce sweating to relieve superficial manifestations, promote lung circulation and calm asthma. In this formula, Ephedra is the ruling herb to induce sweating to relieve exopathogens and promote lung circulation to relieve asthma. Gui Zhi detoxifies the muscles and disperses cold, which helps Ephedra to generate sweat, and is the subject medicine. Adjuvant almond, with ephedra, is a declarative and a descending, in order to restore the declination of lung qi and enhance the function of declaring the lung and relieving asthma. Glycyrrhiza glabra harmonizes all the medicines, and can moderate the combined harshness of hemp and gui, so as to achieve sweating without hurting the right, which is the adjuvant medicine. If the symptoms of asthma and phlegm are mild: remove the cinnamon branch, add suzy, half asia; if the nasal congestion and runny nose are heavy, add cang er, catkins; if the dampness is accompanied by soreness of the bones, add atractylodes, coix seeds; if the internal heat is irritating and dry, add gypsum, scutellaria. Gui Zhi Tang is composed of Gui Zhi, Paeonia lactiflora, roasted licorice, ginger and jujube. It is mainly used for the symptom of exterior wind-cold and superficial deficiency. Clinical manifestations include headache and fever, sweating and vomiting, dryness of the nose, white fur and no thirst, and a slow or weak floating pulse. The main effects are to detoxify the muscles and publish, and harmonize the Ying and Wei. In this formula, Gui Zhi relieves the muscles and expels the wind and cold from the exterior, while Paeonia lactiflora benefits Yin and astringes Ying. The combination of Gui and Paeonia lactiflora, one treats the strong Wei and one treats the weak Ying, and the combination harmonizes the Ying and Wei. The ginger is pungent and warm, which not only helps the cinnamon branch to release the muscle, but also warms the stomach and stops vomiting. Jujube is sweet and calm, both to benefit the qi and nourish the spleen and produce fluid. The use of roasted licorice is two: one for the adjuvant, benefitting the qi and the middle, combined with cinnamon to detoxify the muscle, combined with peony to benefit the yin; one for the make up of the drug, harmonize the drugs. Therefore, although there are only five herbs in this formula, the combination is strict and there is tonicity in dispersal. If the wind and cold are severe, add Fangfeng, Thornbush and Tempeh; if the body is deficient, add Huangqi; if cough and asthma are also seen, add Almond, Su Zi and Mandarin.