Earlier, there were no officially recognized cures, though there were herbal treatments available. Many people took to dyeing their hair in an attempt to hide the whites and the greys amid the natural black hair.
However, nowadays there are quite a few natural cures being claimed. One of these is the use of backstrap molasses. You can use these and see the effects after a few weeks. However there have been people for whom this remedy has not worked.
Besides this, there are other natural methods of reducing grey hair as well. These include using the Amla fruit , bee pollen, supplements of zinc and copper, vinegar, hydrogen peroxide inhalation, and a range of other such treatments.