<human>:  Can you tell me the health concerns for having fluoride in the drinking water?
<bot>: Fluoride is generally considered safe. In high enough doses, fluoride can damage the bones and tooth enamel, but is probably unlikely to reach that level in drinking water. In animal studies, very high levels of fluoride did have some negative effects on the thyroid, however. While there are likely risks associated with high levels of fluoride in drinking water, I’d say this is unlikely to be a major concern.