Balkan endemic nephropathy is a chronic tubulointerstitial kidney disease unique to residents of farming villages along the Danube River and its tributaries in southeastern Europe. It is closely associated with upper urothelial cancer.

Evidence suggests that the region has a high density of plants, most likely Aristolochia clematitis, containing aristolochic acid which is ingested in the regional diet, supposedly by contaminated seeds in locally baked bread. The same aristolochic acid from Aristolochia fangchi was identified in certain Chinese herbs (slimming pills) sold in Belgium as the cause of upper urothelial cancer and end-stage renal disease.

Onset of Balkan endemic nephropathy is insidious and progresses slowly over a decade or two to renal failure. Pathologic signs include tubular dysfunction, glomerular sclerosis, and interstitial edema in early stages. Advanced disease is characterized by global sclerosis, progressive kidney and tubular atrophy, and interstitial fibrosis. Signs of aminoaciduria and renal glucosuria may be present. Normochromic normocytic anemia develops, and kidney size decreases as disease progresses. Up to 50% of affected patients acquire transitional cell carcinoma of the upper urothelial structures, including ureter, renal pelvis, and urinary bladder. Nonspecific symptoms include lethargy, fatigue, weakness, pallor, lumbar pain, and copper-colored hyperpigmentation of palmar and plantar surfaces. Vascular lesions and glomerular lesions from periglomerular fibrosis and deterioration of the kidneys are also present.

Prevention requires removing the offending aristolochic acid (contaminated seeds) from the diet.

Management includes dialysis, kidney removal, and kidney transplant.