In 1994, a 44-year-old woman progressed from normal renal function to advanced renal failure and end-stage renal disease within 8 months. Biopsy revealed extensive interstitial fibrosis with focal lymphocytic infiltration. She received a cadaveric renal transplant in January 1996 and had an uneventful posttransplant course. As a result of a minor motor vehicle accident, the patient had received acupuncture and Chinese herbal medicine for pain relief approximately 5 months before the onset of renal symptoms. After the transplant, analysis of the herbal remedies clearly indicated the presence of aristolochic acid in 2 of the 6 Chinese herbs ingested. Ingestion of aristolochic acid has been linked to a newly defined entity, Chinese herb nephropathy (CHN). This article discusses the history of CHN and its implication in the current case and in other recent similar cases and makes recommendations to avoid future problems caused by unregulated use of herbal medicines. This is the first reported case of CHN in the USA. A 45-year-old woman with end-stage renal failure was referred for a renal transplant workup in February 1995. She had had normal renal function in November 1993 at age 43 and developed malaise, severe anemia, and advanced renal failure 8 months later. Except for a total hysterectomy for uterine fibroids in 1975, she had been entirely well until she suffered a minor motor vehicle accident in 1993 and developed persistent low back pain. Prior to the accident, she had no history of chronic pain or sustained or intermittent use of nonsteroidal anti-inflammatory drugs or other analgesic medication. She had no personal or family history of renal disease, cardiovascular disease, systemic hypertension, or diabetes mellitus. In early 1994, she began receiving acupuncture and Chinese herbal medicine for pain relief.