Coloring hair is very fashionable these days. You can easily see people of all age groups going for hair coloring. People are experimenting with all kinds of colors to look fashionable. It is no longer just natural black or golden people are going for, but they are experimenting with even red, green and blue and coming up with new hair coloring ideas. Hair coloring has been in use since the ancient times. Ancient Greeks used to color or lighten their hair, which identified with honor and courage. They used harsh soaps to lighten or color their hair. There is evidence that ancient Romans also used to color or lighten their hair. Now-a-days, coloring hair is very much popular throughout the world. According to some reports around 75% of women in the U.S. color their hair. Now people do not go for hair coloring just to hide their grey hair but to make a fashion statement as well. Young people experiment with many hair coloring ideas. The market for hair colors is huge spreading all over the world. There are many products for coloring hair available in the market. There are permanent as well as temporary colors. A patch test should be conducted before using any coloring product to see if the person is allergic to the color or not. In the case the person is found allergic to chemicals used in hair colors the use of the same should be stopped immediately. Some people lighten their hair, which is also known as bleaching or decoloring. This process involves the diffusion of the natural color pigment or arificial color from the hair. Permanent hair coloring products contain oxidising agent and an alkalizing ingredient. These chemicals raise the cuticle of the hair fibre so the color can penetrate in the hair fiber. They also facilitate the formation of tints within the hair fibre and bring about the lightening action of peroxide. In the case of temporary colors the the pigment molecules are large so they do not penetrate the cuticle layer. It allows only a coating action that may be removed by shampooing. Temporary hair coloring products come in various forms like shampoos and gels. Normally temporary colors are used to give brighter colors to the hair. It is because temporary hair colourants do not penetrate the hair shaft itself. Instead, these dyes remain adsorbed to the follicle and can be easily removed with a single shampooing. The use of color can cause damage to hair in some cases. It is always better to visit an expert to for coloring hair to avoid any kind of harm done to hair. Coloring hair in some cases can cause breakage of hair strands, hair fall and dry scalp.