Tetracycline teeth are not a contagious disease and are not infectious. Tetracycline is a change in the color of the teeth caused by taking tetracycline drugs, such as tetracycline, oxytetracycline, and gentamycin, during the period of development and mineralization of the teeth (which occurs more often before the age of 7). After tetracycline is metabolized in the body, it is deposited in the inner layers of the teeth, darkening them, and this symptom can be particularly noticeable in infants and young children with early medication. Therefore, tetracycline teeth will not be contagious, tooth discoloration is mainly after sunlight exposure into gray, with age will have pigmentation, the color will be more gray after a long time. The front teeth are usually more severe than the back teeth, but they are not contagious, not from person to person, nor from tooth to tooth.