Mu Tong is an ancient Chinese herb that was derived from Akebia species until the early 20th century. After that time, Clematis species became the main source of Mu Tong until the 1950s. Then, Aristolochia manshuriensis became the main component of this herb. Since the substitution of Aristolochia manshuriensis for Clematis species in preparations of Mu Tong, case reports in China associated the development of renal failure with the use of Mu Tong. 2 Prior to the use of Aristolochia manshuriensis in preparations of Mu Tong, renal dysfunction was not reported in Chinese herbal formularies as a complication of the ingestion of Mu Tong. In 1993, Vanherweghem et al reported a rapidly progressive, fi brosing interstitial nephritis in two young women, who had been treated with an herbal slimming medication supposedly containing Stephania tetrandra and Magnolia offi cinalis . An investigation revealed that seven other women, who also followed a slimming regimen at the same Brussels medical clinic, were admitted to a renal clinic for renal dialysis between 1991 and 1992. Renal biopsies from eight of the nine cases demonstrated extensive interstitial fi brosis without glomerular lesions. Phytochemical analysis of the pills from this weight -reduction clinic detected the presence of aristolochic acids instead of tetrandrine, and this substitution suggested the contamination of these herbal preparations by Aristolochia fangchi . Case reports described the development of interstitial nephritis following the use of other Chinese herbal preparations that contained aristolochic acid. In 1999, a case report described two cases of end -stage renal failure in the United Kingdom following the use of Chinese herbal teas containing aristolochic acid. 5 Additional cases of Chinese herb (aristolochic acid) nephropathy occurred in Asia, Spain, and France.
BOTANICAL DESCRIPTION
The genus Aristolochia contains over 400 species of perennial herbs and shrubs. Misidentifi cation of Aristolochia species as a nonaristolochic acid -containing plant species occurs with a variety of Chinese herbs from Akebia, Asarum, Clematis , and Cocculus genera. Aristolochic acids also occur in several species of butterfl ies (e.g., Atrophaneura, Battus, Pachliopta, Troides ), which feed on Aristolochia species.