Sir, fluorosis is an important clinical and public health problem in several parts of the world where natural levels of fluoride are high, with global prevalence of about 32%.1,2 Water fluoride levels in India range from 2-29 ppm, whereas the permissible level in drinking water according to the WHO standard is 1.0-1.5 ppm.3

The conventional methods of fluoride removal include: precipitation, ion-exchange, reverse osmosis and absorption but all these methods are relatively expensive.2 Consequently, there is continuous research into a relatively inexpensive, easy and faster method of defluoridation. The use of natural products has recently been rediscovered by water-supply technologists and is being further developed with more scientific rigour.1 Recently, researchers in India have developed a filter system based on a medicinal herb, which can quickly and easily remove fluoride from drinking water. Tridax procumbens – a medicinal herb has been tested for the extraction of heavy metals from water. Singanan has suggested this medicinal herb as a biocarbon absorbent for fluoride.4 When this herb is loaded with aluminium ions it is possible to create a safe biocarbon filter that readily absorbs fluoride ions from water. These trials show that it takes just three hours to remove 98% of fluoride with just 2 g of the biocarbon filter, which might provide an inexpensive way to defluoridate water in regions where the natural level of this mineral is high including in India, China, Sri Lanka, the West Indies, Spain, Holland, Italy, Mexico, North and South America.4