The common causes of black wounds are pigmentation, blood seepage, infection, etc. The details are as follows: 1, pigmentation: wounds may be accompanied by pigmentation in the healing process, such as fibrous tissue proliferation, patients who belong to the keloid, may be accompanied by black wounds. This situation belongs to the physiological response of the individual differences of patients, and is not an inflammation or infection of the wound. 2, blood seepage: in the process of wound closure may be accompanied by a small amount of blood seepage, if in the process of blood seepage of wounds accompanied by the wound of the scabs, the performance of the local bruises, black, this time, through the enhancement of the drug change, remove the local scabs, you can clear the local performance of the darkness. 3, infection: infection occurs in the recovery process of wounds, manifested by more pus, black. If the wound is infected during the recovery process, which is manifested by the accumulation of more pus or purulent secretion, it may delay the healing of the wound, form granuloma during the healing process, or even chronic inflammation, which will lead to localized blackening.