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The Fluoridation of Drinking Water

Linus Pauling, Ph.D.
29 November 1967

Over a period of more than a decade I have studied the available information about the fluoridation of drinking water I have reached the conclusion that the presence of fluoride ion in drinking water in concentrations about equal to the average for natural water is beneficial to the health, especially because of the protection that it provides against dental caries, and that there is no evidence for detrimental effects comparable in significance to the beneficial effects. I support the actions of city, state, and national governments in ordering that public supplies of drinking water be brought to this level by the addition of fluoride, in case that the water is deficient in fluoride, and by removal of some of the fluoride if there is an excess of fluoride in the water supply.

Fluoride as a Poison

Fluoride in large amounts is a poison. In small amounts it is beneficial to human beings. In this respect fluoride ion is similar to many other substances, such as vitamin D, that are harmful in large amounts but are required in small amounts for life and good health of human beings. Another example is copper. Copper sales are poisonous, but a small amount of copper is essential for the health of human beings.

Fluoride Ion as an Enzyme Inhibitor

It is known that at certain concentrations fluoride ion acts as an inhibitor of some of the enzymes present in the human body. The available evidence indicates that the fluoride ion present in average natural waters or in waters that have been fluoridated according to the standard present-day practice does not cause harmful effects to human beings by inhibiting enzyme action.

The Mottling of Teeth by Fluoride Ion

Drinking water containing a larger than average amount of fluoride ion causes mottling of the teeth with white spots. In general, only mild or very mild mottling of the enamel is caused by the concentration of fluoride recommended in the fluoridation of drinking water. The disadvantage of occasional mild mottling of the enamel is far outweighed by the advantage of great decrease in dental caries.


This statement was sent to Dr. Stephen Barrett in March 1981.

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This page was posted on July 8, 2002.