The harmful effects of hair coloring include affecting hair texture, damaging hair follicles, and causing allergies. Hair dyeing is the use of plant and chemical pigments to dye hair to the desired color. Hair dyes have a certain effect on the hair, which may lead to dry and shapeless hair; when dyeing hair, the dye will come into contact with the scalp, which may damage the hair follicles on the head, inducing folliculitis, and in severe cases, hair loss may also occur. If you are allergic to the ingredients in the hair dye, you may have an allergic reaction, and your scalp will show redness, swelling, itching, pain and other allergic reactions. Hair dyeing is more harmful to the human body, so in general it is not recommended to dye hair frequently so as not to affect the health of the body. Appearance of the above infection or allergy symptoms recommend that patients go to a regular medical institution in time to avoid delays in the condition.