Coloured hair quandary

I HAVE queries regarding my hair texture. I dye my hair practically every three months in order to cover up the grey hair. Of late, friends have been recommending dye hair with herbal ingredients instead of chemical ones. My hair has become very dry and there are split ends. Will herbal ingredients have any harmful effects on the hair? Are there any other solutions which I can resort to so that my hair becomes smooth and manageable? – Connie

According to Shiseido Professional senior technical manager, Steven Chan, there is a clear difference between the ingredients used in professional colour dyes and herbal colour dyes.