Why would the listerine total care not be suitable for children under 12 years?

Fluorosis. The direction actually say to consult a dentist or doctor if the child is under the age of 12. It is important that the child is old enough to not swallow it and to use it properly. This is when the children's permanent teeth are exfoliating so it's important that they don't ingest high amounts of Fluoride so they don't get fluorosis. Fluorosis is brown staining on teeth.