The black navel may be caused by the following reasons: 1, may be due to improper cleaning of the navel caused by the accumulation of many bacteria and metabolic waste, there will be a black color at the navel, sometimes accompanied by the accumulation of mud, you can use soap and water or alcohol for cleaning, can achieve the effect of improving the black navel. 2, some patients are due to individual differences, will be in the navel position due to skin color pigmentation This is a normal physiological phenomenon. 3, may be due to the blockage of blood vessels around the navel of the patient, resulting in local ischemia, hypoxia, resulting in black, will be accompanied by a decrease in skin temperature and local pain in the navel. It is recommended to go to the hospital for an ultrasound examination to determine the location of the arterial stenosis or occlusion, and to carry out treatment according to the plan given by the doctor to restore the arterial blood flow and improve the effect of the blackening of the navel.