It is not true that kidney failure will definitely show darkening of the face, and not necessarily all kidney failure patients will have darkening of the face. Kidney failure patients because of the cause of the disease and lead to partial loss of kidney function, so often lead to the body every day to produce a large number of toxins as well as excess water can not be effectively discharged through the kidneys, causing toxin accumulation in the body, which can lead to abnormalities in various systems, when toxins in the skin deposition, it may cause skin color darkening, which is the face black. However, if the patient is in the early stage of renal failure, the condition is not serious, or the treatment effect is good, the accumulation of toxins may not occur resulting in the darkening of the face. Therefore, patients with renal failure may not always have black face. Patients with renal failure are advised to go to regular hospitals for timely consultation and targeted treatment or therapy under the guidance of doctors.