Toxic effects of chronic fluoride ingestion on the upper gastrointestinal tract

J Clin Gastroenterol. 1994 Apr;18(3):194-9. doi: 10.1097/00004836-199404000-00004.


In a prospective case controlled study, we evaluated the adverse effects of long-term fluoride ingestion on the gastrointestinal tract. Ten patients with otosclerosis who were receiving sodium fluoride 30 mg/day for a period of 3-12 months, and 10 age- and sex-matched healthy volunteers were included. They were all evaluated clinically and subjected to a real time ultrasound examination, upper gastrointestinal endoscopy, and biopsies from the gastric antrum and duodenum. The biopsies were subjected to a rapid urease test as well as light and electron microscopic examinations. Ionic fluoride was estimated in the serum, urine, and drinking water using an ION 85 Ion Analyzer. Seven subjects (70%) ingesting fluoride had abdominal pain, vomiting, and nausea. Petechiae, erosions, and erythema were seen on endoscopy in all the subjects, but not in the controls. Histological examination of the gastric antral biopsy showed chronic atrophic gastritis in all the subjects but in only one (10%) healthy volunteer. Scanning electron microscopic examination showed "cracked-clay" appearance, scanty microvilli, surface abrasions, and desquamated epithelium in the subjects ingesting fluoride, but not in the controls. We conclude that long-term fluoride ingestion is associated with a high incidence of dyspeptic symptoms as well as histological and electron microscopic abnormalities.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Case-Control Studies
  • Digestive System / drug effects*
  • Duodenum / drug effects
  • Female
  • Fluorides / toxicity*
  • Gastric Mucosa / drug effects
  • Gastric Mucosa / ultrastructure
  • Humans
  • Intestinal Mucosa / drug effects
  • Intestinal Mucosa / ultrastructure
  • Male
  • Middle Aged
  • Prospective Studies
  • Pyloric Antrum / drug effects
  • Sodium Fluoride / toxicity


  • Sodium Fluoride
  • Fluorides