Rifampicin (Rifaximin), a derivative of rifamycin, was developed by Alfa Italy. It was marketed in Italy as an anti-infectious diarrhea drug in 1987 and is still widely used abroad. Approved by SFDA in 2004, it has been used in clinical practice in China. It is a semi-synthetic antibacterial drug of rifamycin. It has a broad antibacterial spectrum and strong antibacterial activity. It can form a higher concentration of blood in the intestinal tract. It can inhibit Staphylococcus aureus, Streptococcus faecalis and Salmonella in gram-positive aerobes, which belong to the genus Salmonella in Gram-negative aerobic bacteria. Shigella and Escherichia coli, Yersinia enterocolitica and Gram-positive anaerobic bacteria all have high antibacterial activity. The mechanism of its action is to inhibit bacterial polymerase, block the transcription process of RNA, and then inhibit the synthesis of bacterial protein, thus reducing the production of ammonia. 1) the antibacterial activity is strong, and the antibacterial spectrum is wide. It has bactericidal effect on most gram-positive bacteria and gram-negative bacteria (including aerobic bacteria and anaerobic bacteria), and the effect on gram-positive bacteria is stronger than that on gram-negative bacteria. 2) it is not absorbed by gastrointestinal tract, and its concentration is very high in the intestinal tract. It can kill the pathogen of intestinal tract and play an anti-bacterial effect quickly in the local area, and it is not necessary to use antispasmodic and adsorptive drugs in combination with intestinal tract.