There's a question mark over the effectiveness of Javaan 50, a multivitamin that medical trials had shown was effective against Alzheimer's.
Scientists have questioned the validity of the research, which appeared in three medical journals. The man at the centre of the controversy is Prof Ranjit Chandra, who happens to hold the patent for Javaan 50, which is available in North America.
Chandra started testing the supplement in 1992 when his first results were published in The Lancet. He followed this up with another trial, published in Nutrition in 2001. A statistician at the British Medical Journal, who reviewed the very impressive results from the Nutrition paper, concluded that the data had 'all the hallmarks of being entirely invented'.
For his part, Chandra has continued to defend his corner, but support for his position seems to be disappearing.
(Source: British Medical Journal, 2004; 328: 67).