BOSTON, Aug 8: A drug normally used to treat an adult form of leukemia may be able to restore color to grey hair, a team of puzzled French doctors reported on Wednesday.

Of the 133 people they treated with the drug, sold under the brand name Gleevec by Swiss drugmaker Novartis AG, five men and four women who started out with grey hair ended up with their old color back.

Describing the finding as a “mystery, the doctors, led by Gabriel Etienne of the Universite Victor Segalen in Bordeaux, asked in a letter published in Thursday’s New England Journal of Medicine whether anyone else had seen similar side-effects.

One of the doctors told Reuters the rate may actually be higher than the level they found.

Francois-Xavier Mahon said many of the patients, particularly the women, had dyed their hair, making it difficult to determine how many might have experienced the change.

The process of color restoration usually took about five months, although in one patient the hair color returned after 14 months of therapy.

Mahon said people should not be taking the drug to restore hair color but added that laboratory studies are under way to explore the surprising side effect.—Reuters