Black earwax may be due to oxidization of earwax and bleeding in the ear canal. 1. Oxidation of earwax: If the earwax stays in the ear canal for a long time and is not cleaned up in time, coupled with the fact that the earwax is rich in oil, it will turn black when it is oxidized. 2. Bleeding in the ear canal: When the capillaries in the ear canal break and bleed because of ear digging, hard object knocking, external force hitting or eczema cracking in the external ear canal, it can cause the earwax to be stained with blood, and the blood will turn into black after oxidized, resulting in the surface of the earwax being black. If the earwax is black, you should go to the regular hospital in time to find out the cause of the disease and choose the suitable method for your treatment under the guidance of professional doctors.