2 years old baby erupted should be milk teeth, normal milk teeth than permanent teeth white, if the baby’s teeth appear yellowing, most parents do not pay attention to the baby’s oral hygiene caused. In addition, tetracycline teeth can also lead to yellow teeth discoloration. 1, do not pay attention to oral hygiene: the baby eats food attached to the surface of the teeth, at this time the baby has not formed oral care awareness, and parents usually do not pay attention to the baby oral hygiene, resulting in the accumulation of soft scale on the teeth, the phenomenon of yellowing teeth. Parents should brush baby’s teeth every morning and evening to reduce the yellowing of teeth. If there is caries, even brushing can not be removed, should go to dentistry for treatment; 2, tetracycline teeth: tetracycline drugs can enter the fetus through the placenta, resulting in teeth creamy yellow, yellowish, yellow-brown, etc. The most fundamental way to avoid tetracycline teeth of 2-year-old baby is to try not to take tetracycline during pregnancy.