More than 20 years ago a Belgian report described nine women with rapidly progressive fibrosing interstitial nephritis who either required dialysis or showed progressive renal impairment.1 All of the women had taken a slimming regimen that included herbs of the Aristolochia family, which have been known to be nephrotoxic and carcinogenic since the 1980s. Within five years, this group of nephrologists identified more than 100 patients with aristolochic acid nephropathy, almost half of whom were later found also to have tumours of the upper urinary tract.2 Case reports and series from around the world followed.3 Aristolochic acid was classified as a human carcinogen by the International Agency for Research on Cancer, and regulatory authorities in Europe, North America, and several other regions issued alerts or instituted import bans. However, these regulatory measures have been wholly inadequate at eliminating this preventable disease, with a recent report describing 300 cases of aristolochic acid nephropathy from a single centre in Beijing.4

Herbs that contain aristolochic acid are often found in traditional Chinese preparations, particularly—although not exclusively—in those with fang ji …