Tetracycline is a broad-spectrum antibacterial drug and should not be used in children under 8 years of age to avoid serious adverse reactions. Tetracycline has certain effects on the development of fetal, neonatal and infant bones, and can also lead to enamel dysplasia and yellowing of teeth in pediatric milk teeth and permanent teeth, resulting in tetracycline teeth. Tetracycline is a major stimulus to the gastrointestinal tract of children, easily causing disruption of the normal flora in the body, nausea, vomiting, diarrhea, indigestion, loss of appetite and other symptoms, and can also inhibit the production of B vitamins and vitamin K bacteria in the intestinal tract of children, resulting in vitamin deficiency. Therefore, the application of tetracyclines should be contraindicated in children under 8 years of age to avoid adverse effects. In addition, allergic reactions can occur in children after taking tetracycline, such as drug rash, anal and vulvar itching, and long-term or large amounts of use can cause liver and kidney damage, parents need to pay attention.