Tetracycline is an all-natural antibiotic that rapidly inhibits bacterial growth, works by interfering with bacterial protein synthesis, and kills bacteria at very high concentrations. Tetracycline is a broad-spectrum antibiotic that inhibits both gram-staining positive and gram-staining negative bacteria, and also has a relatively strong inhibitory effect on rickettsia, mycoplasma, chlamydia, and can also inhibit certain spirochetes. Tetracycline is ineffective against typhoid, tuberculosis, fungi and viruses. Tetracycline was once used for a long time as the main antibiotic for patients’ anti-infection treatment together with hygromycin. Later, due to the increasing number of drug-resistant bacteria, tetracycline antibacterial treatment became less and less effective, and there were more adverse reactions to tetracycline, which has now been largely eliminated. Tetracycline can now also be used in combination with other drugs to treat peptic ulcers caused by Helicobacter pylori infection; it can also be used for infections of Mycoplasma, Chlamydia, and Rickettsia, and is generally no longer used as the drug of choice.