It is now a well-established fact that fluoride in drinking water can cause "non-ulcer dyspeptic" complaints in human subjects. The main complaints are:

1. Nausea
2. Loss of appetite
3. Pain in the stomach
4. Gas formation and bloated feeling
5. Constipation followed by intermittent diarrhoea
6. Head ache

The investigations carried out on Human patients during the period 1992-1996 and the results obtained are reported in the following publications.

1. Fluoride ingestion and its correlation with Gastro-intestinal discomfort. FLUORIDE, 1992, 25 (1), 5-22.
   A.K. Susheela, Taposh K. Das, I.P. Gupta, R.K. Tandon, S.K. Kacker, P. Ghosh and R.C. Deka.
2. Alimentary tract and pancreas: Fluoride as a possible aetiological factor in non-ulcer dyspepsia. JOURNAL OF GASTROENTEROLOGY & HEPATOLOGY, 1992, 7, 355 359. I.P. Gupta, T.K. Das, A.K. Susheela, S. Dasrathy and R.K. Tandon
3. Prevalence of endemic fluorosis with gastro-intestinal manifesta­tions in people living in some North-Indian villages. FLUORIDE. 1993, 26 (2), 97-104. A.K. Susheela, Arbind Kumar, Madhu Bhatnagar and R. Bahadur.
4. Toxic Effects of Chronic fluoride Ingestion on the Upper Gastrointestinal Tract. J. CLIN. GASTROENTEROL 1994; 18(3) 194 9. T.K. Das, A.K. Susheela, I.P. Gupta, S. Dasarathy and R.K. Tandon.
5. Epidemiological studies of health risks from drinking water naturally contaminated with fluoride, A.K. Susheela. In: Assessing and managing health risks from drinking water contamination: AP­PROACHES AND APPLICATIONS. Editors ERIC G. REICHARD & GIOVANNI A. ZAPPONI 1995- Page No. 123 - 134,  (Proceedings of Rome Symposium September 1994) International Association of Hydrological Sciences. IAHS Publication No. 233 (ISSN 0144 - 7815) IAHS Press: Oxfordshire OX 10 8BB, U.K.
6. Gastroduodenal manifestations in patients with skeletal fluorosis.J. GASTROENTEROL 1996; 31:333 337. S. Dasarathy, Taposh K. Das, I.P. Gupta, A.K. Susheela and R.K. Tandon.