The heart and the small intestine are mutually exclusive, i.e., the heart and the small intestine are interconnected and influence each other. Surface and inside, inside and outside. Chinese medicine said that the viscera within, viscera outside, the phase of the table that is the meaning. Heart for the dirty, small intestine for the bowels. The heart of the blood, the heart of the warmth of the sun, the heart of the blood of moistening, help the small intestine of the chemical function, so that the water and grain in the small intestine fully differentiated into nutrients that can be utilized by the body and the dregs; the small intestine main compounds, urination don’t clear and turbid, absorption of the essence of the water and grain and the water, which is the thick part of the spleen qi transfers with the heart, the blood to raise its heart. The heart and small intestine through the meridians of the mutual affiliation constitutes the relationship between the surface and the inner. Therefore, the heart meridian real fire can be transferred to the small intestine, causing urine, urine red, defecation burning and other small intestine real heat of the disease; Conversely, the small intestine has heat, can also be smoked in the heart through the meridian, can appear upset, tongue red and vesicose and other diseases.