In daily life, many people often appear such a phenomenon: usually no constipation symptoms, but after the cold suddenly constipation, or is usually constipated, once the cold constipation will aggravate, and even the previous laxative methods and drugs will fail, so what exactly is the connection between the cold and constipation? Chinese medicine believes that the lung and large intestine, where the lung can be commonly understood as the entire respiratory system of the morphological function of the synthesis, while the large intestine is simply understood as the common impression of the large intestine. The “Taiping Sheng Hui Fang” in the “large intestine, the lung’s internal organs, the conduction of the internal organs, the material out of the. The essence of water and grain, turned into blood, travel in the meridians. Its dregs travel in the large intestine. The lung and large intestine, and the lung is the main gas, its waiting for the body of the skin.” The “Su Ling Wei Yun – Volume 4” points out that “the lung and large intestine surface and inside the same gas, the lung gas into fluid, nourishing the large intestine, the intestine smooth and easy.” The conduction function of the large intestine depends on the propagation and purification of the lung qi, the lung qi descends, the large intestine qi also descends, in order to play its conduction function, so that the stool is discharged smoothly. In addition, the lung is the main regulator of water channels, which can transport fluid to moisten the large intestine, so that the stool is not dry. The causes of constipation due to colds are as follows: 1, external evil attacking the lung health, on the one hand, the lung’s declination function is dysfunctional, lung gas is depressed, the internal Qi is not accessible, the conduction function of the large intestine is affected; on the other hand, the lung can not normal transmission of fluid, the large intestine is not moistened, then constipation. 2, the evil is contending with each other, the evil is too strong, will inevitably lead to deficiency of positive energy, the large intestine conduction to promote the decline in function, and lead to constipation. If you feel the heat, the fluid depletion to form heat constipation, if you feel the cold, the cold condensation stagnation to form cold constipation. In addition, wind-cold cold medicine is too cold, wind-heat cold medicine is too warm will also lead to cold constipation and heat constipation. 3, the external evil invasion, the righteousness is not enough, the whole body will be in a relatively weak state, the spleen and stomach transport function will also be reduced, once the diet is a little careless, it may lead to stagnation, and then heat and injury to the Jin cause intestinal dry Jin deficiency secondary to constipation. Therefore, after the cold should be actively treated to prevent secondary constipation, of course, must be the correct use of drugs, light diet, if necessary to seek medical treatment.