Da Cheng Qi Tang is a classic formula for the treatment of Yang Ming internal heat syndrome in the Treatise on Typhoid and Miscellaneous Diseases by Zhang Zhongjing, a famous doctor in the Han Dynasty. The so-called Yangming internal organs solidity refers to the abnormal function of the gastrointestinal tract in transporting and transforming, forming dryness and dampness, food accumulation and actual heat in the gastrointestinal tract, which is commonly known as “gastrointestinal fire”. The manifestations are dry mouth, constipation, foul stool and vector gas, abdominal distension, abdominal pain, loss of appetite, bad breath, yellow, thick and greasy tongue coating, or dry heat and irritability in the afternoon. This formula is composed of four herbs: rhubarb, citrus aurantium, houpu, and mannite. Rhubarb, a cold laxative, can remove heat from the intestinal tract, and clear the internal organs and laxative, which is the “scavenger” of the intestinal tract, clearing the intestinal waste, and has the effect of pushing out the old and bringing in the new. Citrus aurantium can enhance the excretory power of the intestine, enhance intestinal peristalsis, and relieve abdominal distension. Hou Pu, which can also remove gas and distension, enhance intestinal peristalsis, and has a synergistic effect with Citrus aurantium. Mangosteen can increase the moisture of the intestine, moisten the intestine, soften the tangible food and fecal accumulation in the intestine and make it easier to excrete, and has a synergistic effect with Rhubarb. In summary, Da Cheng Qi Tang can play the role of clearing heat from the internal organs, softening and dispersing hardness, and it has the effect of “drawing fire from the bottom”. Because of the strong laxative effect of this formula, it must be accurately identified when used. It is often used clinically for acute intestinal obstruction, acute pancreatitis, acute cholecystitis, acute appendicitis, acute respiratory distress syndrome and other diseases with the above-mentioned manifestations.