Almost every third person in his or her 20s these days is developing grey hair. Maybe it is a sign of the stressful times we live in. Even though it can't be prevented much it can be concealed with hair colours. Now there are many artificial colours available in the market but they do have certain side effects. Hair dyes may contain certain chemicals that go by the name of secondary amines and these can react with exhaust from vehicles as well as tobacco smoke to form other compounds called N-nitrosamines that have been implicated in cancer. Although you may