Among them, henna leaf and walnut husk were the most efficient natural hair dyes and at present henna (Lawsonia inermis L.) is still the most commonly used natural plant for this purpose. In principle, a wide range of vegetables might be used as starting material for “green” hair dye compositions but the exploitation of natural pigments for hair dyeing is more complicated than that on the textiles that can use longer exposition times, higher temperatures and presence of mordants [2b,c].