Browning disease is a rare hereditary disorder of amino acid metabolism. The disease is hereditary, often with a history of consanguineous marriage, and is present from birth, most often after the age of 30 years, more males than females, in a ratio of about 2:1. The cause is the lack of heme-urea oxidase in the liver, resulting in the excretion of large amounts of unoxidized heme-urea in the urine and its deposition in various tissues and organs of the body. If black uric acid is deposited in the joint structure, it causes brown yellows disease arthritis. 1.Clinical manifestations The main symptoms are brownish-yellow pigmentation of the skin, sclera and cornea, the ear, nose and cartilage may become blue, the edge of the tympanic membrane is grayish-black, and the hearing is often diminished. If uric acid is deposited in the aortic valve and mitral valve, the valve becomes stiff and murmurs appear. Urinary tract diseases often include black prostate stones. Bone and joint changes generally erode the spine first, followed by the knee, shoulder and hip are involved in succession, the incidence of spondylitis is 10% to 15%. The joint tissues of the extremities also have degenerative changes due to pigmentation, loss of elasticity of articular cartilage, thickening of synovial fibrosis, erosion of subchondral bone and cystic changes with dense bone, sclerosis and formation of bone redundancy, which can lead to joint ankylosis. The synovial membrane of the joint is villi-like hyperplasia and pigmentation, and there is pigmented cartilage debris in the joint fluid. 2.Treatment There is no specific effective treatment for brown yellows arthritis. Degenerative changes are the same as in hyperplastic arthritis. Patients should perform appropriate activities, but should not add weight to the joints. If the patient has joint pain and severe motor dysfunction, arthroplasty may be an option for treatment. Theoretically, vitamin C should be prohibited because it hinders the oxidation and coagulation of black uric acid which has the effect of inducing browning disease, and some foods rich in it should be used with caution. Dietary intake of phenylalanine and tyrosine (e.g. natural proteins) should be controlled.