Excess of fluorides in drinking water or food causes fluorosis. It affects most of the tissues of human body and is incurable but it can be prevented if it is diagnosed in early stages. The onset of fluorosis can be delayed and its severity is minimized by consumption of food rich in calcium and vitamin D. A useful technique has been recently developed in India, the SA/GAG (Sialic acid/ Glycosaminoglycans) test for early detection of the disease. Fluorosis is diagnosed in late stage by radiographs of bones and joints. Besides these methods a home based approach has been also developed for early detection of the disease which consists of some physical tests, gastrointestinal complaints and general manifestations. It is very useful in rural areas. The following study shows the role of fluorides in the crippling disease of school children at Narketpally village in Nalgonda district of Andhra Pradesh.