I have only read in one report that henna can cause liver or kidney problems in only certain people who have a certain condition and I cant recall what it is. Every other thing I have read about it,says it is safe. If opting to cover grey hair, it is best to use a good organic brand of henna and use strong coffee instead of water to mix it with. I dont know what it does to grey hair but this is what they suggest. I have used henna as a conditioner and if it has color, it will turn hair a purple color but that depends on the type of henna used. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com