Rapidly progressive interstitial renal fibrosis has recently been reported in young women who have been on a slimming regimen including Chinese herbs. We examined four nephroureterectomies performed in three patients prior to or at the time of transplantation to determine the nature and topography of the kidney and urinary tract lesions in Chinese herbs nephropathy (CHN). Extensive, hypocellular, interstitial sclerosis, tubular atrophy and global sclerosis of glomeruli decreasing from the outer to the inner cortex, including the columns of Bertin, were observed in the four kidney specimens, together with severe fibromucoid to fibrous intimal thickening, mainly of interlobular arteries, normal or collapsed residual glomeruli, and mild to moderate atypia and atypical hyperplasia of the urothelium. In addition, bilateral pelvi-ureteric sclerosis was observed in one case. With the exception of the latter, these lesions are very similar to those described in Balkan endemic nephropathy (BEN). The clinical presentation of the patients was also similar to that observed in BEN: normal blood pressure, aseptic leukocyturia, low grade low molecular weight proteinuria, early and severe anemia. In conclusion, on morphological and clinical grounds, CHN appears similar to BEN. A common etiologic agent, aristolochic acid, is suspected. The known carcinogenic potential of this compound, taken together with our finding of multiple foci of cellular atypia of the urothelium suggest that CHN patients should undergo a regular follow-up for urothelial malignancy.