Adrenal cortex hormone drugs. It has anti-inflammatory, anti-allergic, anti-rheumatic and immunosuppressive effects. Its mechanism of action is: 1. Anti-inflammatory effect: It reduces and prevents the tissue's response to inflammation, thereby reducing the manifestations of inflammation. It can inhibit the accumulation of inflammatory cells, including macrophages and leukocytes, at the site of inflammation, and inhibit phagocytosis, the release of lysosomal enzymes, and the synthesis and release of inflammatory chemical mediators. 2. Immunosuppressive effect: It includes preventing or inhibiting cell-mediated immune responses, delayed allergic reactions, reducing the number of T lymphocytes, monocytes, and eosinophils, reducing the ability of immunoglobulins to bind to cell surface receptors, and inhibiting the synthesis and release of interleukins, thereby reducing the transformation of T lymphocytes into lymphoblasts.

It has a broad-spectrum antimicrobial effect in vitro, including aerobic Gram-negative and Gram-positive bacteria, anaerobes, Rickettsia, spirochetes and Chlamydia. It has a bactericidal effect on Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis; it only has an antibacterial effect on anaerobic bacteria such as Staphylococcus aureus, Streptococcus pyogenes, Streptococcus viridans, Group B hemolytic Streptococcus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella typhi, Salmonella paratyphi, Shigella, Bacteroides fragilis, etc. Pseudomonas aeruginosa, Acinetobacter, Enterobacter, Serratia marcescens, indole-positive Proteus, methicillin-resistant Staphylococcus and Enterococcus are usually resistant to chloramphenicol. Chloramphenicol is fat-soluble, enters bacterial cells by diffusion, and reversibly binds to the 50S subunit of bacterial ribosomes, inhibiting the formation of peptide chains, thereby preventing protein synthesis.