I had to write in response to Sam Barsam (Letters, June 15) to warn people of the potential side-effects of water fluoridation.

Mr Barsam seems unaware of them, saying, "the benefits considerably outweigh the risks and everyone, from children to the elderly, would benefit."

I agreed with some of the other comments he made elsewhere in his letter but I had to take issue with this piece of misinformation.

Fluoride may help kill bacteria in the mouth when used as a mouthwash but it is so toxic, it can kill more than just them.

Indeed, if a whole tube of fluoride toothpaste was ingested by an infant it could be fatal.

Dean Burk of the US National Cancer Institute estimated that fluoride in public water supplies caused more than 10,000 cancer deaths per year. He said, "fluoride causes more human cancer death and causes it faster than any other chemical."

In 1977, more research, this time by Burk and Yiamouyiannis, compared cancer death rates in ten fluoridated and ten non-fluoridated cities in North America.

Their project demonstrated that, for the first ten years (1940-1950), when none of the cities were fluoridated, the average cancer deaths were virtually identical. But after 1950, there was a major increase in cancer deaths in the fluoridated cities, while the non-fluoridated cities had much lower cancer rates.

Poison in our drinking water a good idea? I think not, Mr Barsam.

-Veronica Walton LCH MARH, The Homoeopathic House, Carlisle Road, Hove