Chinese medicine believes that the external etiology of interstitial lung disease can be divided into four aspects: First, exogenous: exogenous evils, including the six evils, plague and so on, but mostly wind, heat. Environmental toxicity and occupational dust. Third, other diseases mistreatment: the most common is the misuse of sweat, spit, under the law, or over the use of bitter and cold yin agent, heavy loss of fluid, damage to the lungs and stomach of the yin, the stomach can not be upward transmission of fluids, the upper jiao heat, so that the lungs are dry fluid dry, hot and dry increasingly depletion of Yin, resulting in yin fluid is difficult to restore the lungs are not clear and clean, declared the loss of the Division of the fluid does not cloth, triggering the occurrence of interstitial lung disease. Fourth, drug side effects: many Western drugs such as antitumor drugs, anti-inflammatory drugs, chemotherapy drugs, etc., can induce this disease.