RESUMO
At present， the incidence and mortality of gastric cancer in China are 10.26% and 12.45%， ranking the second and third places， respectively， in the incidence and mortality of malignant tumors in China. Cancer often goes through three stages： precancerous lesions， carcinoma in situ， and invasive carcinoma. It is of great significance to advance cancer prevention and control to the stage of precancerous lesions. The popularization of digestive endoscopy-assisted diagnosis and treatment has enabled the timely diagnosis and treatment of early gastric cancer and severe dysplasia. However， the endoscopic mucosal resection is not suitable for most precancerous lesions of gastric cancer （PLGC）， and the effective drugs are not available. The long-term clinical dynamic monitoring has imposed considerable physical and mental burdens on patients. Gastrointestinal microenvironment is a dynamic balance system composed of gastrointestinal flora， chemical barrier， mechanical barrier， immune barrier， and gastrointestinal nerves. The imbalance of gastric microenvironment has been proved to be the key mechanism of PLGC. According to traditional Chinese medicine （TCM）， PLGC is a result of long-term interaction between deficient healthy Qi and excessive pathogens. In syndrome differentiation and treatment， PLGC is often believed to be developed from chronic gastritis. Besides， the inflammation-cancer transformation model put forward by Correa and the evolution of its TCM pathogenesis are also considered. Guided by the basic treatment principle of reinforcing healthy Qi to eliminate pathogenic factors， we determined the basic therapeutic methods as follows： invigorating spleen， clearing heat， and resolving dampness. At the same time， such methods as soothing liver and regulating Qi， resolving phlegm and dissipating mass， activating blood and resolving stasis， clearing heat and removing toxin， and tonifying deficiency can be combined based on the results of syndrome differentiation. After discussing the correlation between the imbalance of gastric microenvironment and PLGC and summarizing TCM intervention methods and mechanisms against PLGC from the perspective of gastric microenvironment regulation， this paper believed that TCM improved the gastric microenvironment by regulating the disorder of gastric flora， eliminating the gastric mucosal inflammation， and relieving the abnormal immune response， thereby preventing and controlling the PLGC.
RESUMO
Chinese medicine (CM) decoction placebo is one of the key factors restricting the placebo-controlled clinical trial of CM. In this article, based on the analysis of the diffificulties in preparing CM placebo, the production requirements for placebo were put forward. Moreover, in accordance with clinical practices, a production method and evaluation process of CM decoction placebo was proposed, to provide a reference for clinical research.