What are the signs of fluoride overdose?

Sick or brown spots: Having too much topical Fluoride can make some throw up and that includes digesting fluoridated mouthwashes. If you have water from a well that has high Fluoride levels and are taking Fluoride containing vitamins (infants) then you could be getting too much Fluoride and develope brown spots on your teeth. It is wise to try to have your water tested and watch the baby vitamins but necessary! earl.

Depends how much: We deal with dental fluorosis which is caused by excessive long term exposure to fluoride. Fluorosis looks like white spots or white staining of the enamal. With more acute overdoses, you would feel stomach pains, convulsions, irregular hearbeat with tremors, irregular breathing.