OBJECTIVES Although the nephrotoxic and carcinogenic effects of Aristolochic acid (AA) have already been well documented, there is a distinct lack of evidence on the long-term consumption of Chinese herbal products (CHPs) which either contain Aristolochia herb species, or which have been adulterated by herbs suspected of containing AA (SAA herbs). We set out to identify the risks and to determine the prescription patterns in Taiwan of CHPs containing SAA herbs (SAA CHPs) prior to the promulgation of the regulations banning their use. METHODS A longitudinal analysis was carried out on a randomly sampled cohort of 200,000 patients using 1997-2003 data obtained from the Taiwan National Health Insurance (NHI) reimbursement database. RESULTS During the seven-year study period, a total of 78,644 patients had been prescribed with SAA CHPs on at least one occasion, the majority of whom were females and/or middle-aged. A total of 526,867 prescriptions were issued containing 1,218 licensed SAA CHP items. Over 85% of SAA-exposed patients took less than 60gms of SAA herbs; however, about 7% were exposed to a cumulative dose in excess of 100gms of Xi xin, Mu tong or Ma dou ling. Diseases of the respiratory and musculoskeletal system were the most common indications for the SAA CHP prescriptions. The most frequently prescribed SAA CHPs were Shu jing huo xie tang, Chuan qiong cha diao san, and Long dan xie gan tang, respectively containing Fang ji, Xi xin, and Mu tong. CONCLUSIONS About one-third of people in Taiwan have at some time been prescribed with SAA CHPs, and although the cumulated dosages may not be large, future studies are indicated to safeguard CHP usage.