"The permissible upper limit for fluoride in a tropical country like India is 1.00 ppm (mg/1) but lesser the better as fluoride is injurious to health". This is the latest standard for fluoride issued by the Bureau of Indian Standards (BIS) for drinking water (1992). The cumulative and additive effects of fluo­ride are a cause for concern.

Gastro-intestinal complaints like nausea, vomiting, loss of appetite, pain in the stomach, gas formation and a feeling of having a bloated stomach, con­stipation, intermittent diarrhea are also caused by fluoride ingestion and such complaints should not be dismissed. It can be caused by fluoride enter­ing the body through water, food or even dental products.

Upper gastrointestinal endoscopy using fiber optic Endoscope and punch biopsy material examined under scanning electronmicroscope revealed (1) loss of microvilli on the cell surfaces (2) loss of mucus in the mucosa and (3) "cracked clay" appearance of the cell surfaces of the mucosa compared to normal, healthy mucosa (Fig 1). The following scanning electron micrographs Figs 2 & 3 reveal the damage caused to the human gastro-intestinal mucosa by fluoride.

The health complaints, resulting as a consequence of the structural damage, caused to the mucosa by fluoride intake can be rectified / corrected in a matter of 10-15 days by providing safe water for consumption / or withdraw­ing the source of fluoride entry to the body and it is a fact that drugs are not required for treating "such non-ulcer dyspeptic complaints". Drinking safe water with fluoride as low as possible is good enough to reverse the adverse health complaints within a fortnight.

	Fig.1   Scanning electron micrograph of Gastro-intestinal mucosa of a normal healthy adult individual (control) showing (1) columnar cells studded with microvilli on the cell surface. The microvilli are responsible for absorbing nutrients from the diet and (2) The white mass spread around the mucosa is the mucus which helps in comfortable bowel movement.
	Fig.2:  Scanning electron micrograph of Gastro-intestinal mucosa of an individual suffering from “non-ulcer dyspeptic” complaints, consuming water contaminated with 1.22 ppm (mg/l) of fluoride. Note: The columnar cell surfaces are exposed (naked) as: microvilli are lost presence of scanty microvilli very little mucus secretion seen on the mucosal surface
	Fig.3 :  Scanning electron micrograph of Gastro-intestinal mucosa, of an individual suffering from nun-ulcer dyspeptic complaints; consuming water with 3.2 ppm (mg/L) of fluoride  Note:  The columnar cell surfaces are exposed (naked) and appear: cracked no microvilli no mucus secretions are seen