Use principle: choose according to the stool test results, which type of flora is reduced, then supplement the type of flora; try to stop using antibiotics, antibiotics have a killing effect on the live bacteria in the microecological preparations, the two generally should not be used at the same time, if you have to use antibiotics, you should use microecological preparations that are not affected by antibiotics, such as LOTOR, YIHU, etc.; if there is no suitable preparation to choose, the two types of drugs should be taken as far as possible The time interval is longer. Generally speaking, microecological agents (except physiological fungi such as EVERFINE) can be used simultaneously with antifungal agents. The combination of bacteria is more effective than single bacteria. Microecological agents should be used with other therapies: microecological agents are often used with etiological treatment or symptomatic treatment, even for simple intestinal diseases, they may need to be used with the role of antispasmodic, antidiarrheal, rehydration and other treatments. The principle of rational use of antibiotics: try to use a small dose, with a small dose can achieve the purpose, then do not use a large dose; try to use a narrow-spectrum antibiotics, with a narrow-spectrum antibiotics can achieve efficacy, then do not use broad-spectrum antibiotics; try to avoid oral, for systemic and extra-intestinal infections, try not to give drugs orally, using the injection route of administration; try to protect anaerobic bacteria, no evidence of anaerobic bacterial infection, should try not to use on If there is no evidence of anaerobic infection, antibiotics that kill anaerobic bacteria should not be used; restore the intestinal microecological balance as soon as possible, if the use of antibiotics disturbs the intestinal microecological balance, microecological preparations should be taken as soon as possible to restore the microecological balance. Lou Jin, Department of Gastroenterology, Children’s Hospital, Zhejiang University School of Medicine The traditional view is that probiotic preparations are quite safe, and in recent years the literature has reported that bifidobacteria and lactobacilli have been detected in endocarditis, bacteremia, blood, and local infection foci. The factors affecting the safety of probiotic preparations are: (1) pathogenicity and infectivity of probiotics: probiotics are generally not pathogenic, but may be pathogenic after bacterial translocation, and bacterial translocation does not occur in general patients taking probiotics, but in the use of immunosuppressants, immunodeficient patients, and sentient animals, it may occur (2) toxicity of metabolites: bifidobacteria and lactobacilli are not reported to have pathogenic substance production, but Jett et al. (1994) reported that Enterococcus can produce substances that cause cell lysis (3) delivery of drug-resistant plasmids problem: Enterococcus faecalis delivers vancomycin-resistant plasmids (4) probiotics have platelet aggregation, mucosal degradation.