Chen CJ, Yang YH, Lin MH, et al. - Among patients with hepatitis C virus (HCV)-infection, researchers assessed the risk of primary liver cancer (PLC) in relation to taking herbal medicine (HM) containing aristolochic acid (AA) in this prospective analysis with long-term follow up of a nationwide population-based cohort. They selected 223,467 HCV-infected patients using the National Health Insurance Research Database in Taiwan. Among patients who had visited traditional Chinese medicine clinics, they assessed the use of HM containing AA. The participants were observed during the follow-up period of 3,052,132 person-years. An increased risk of developing PLC was seen among HCV positive patients in correlation with increased exposure to AA.