A 58-year-old man ingested an herbal preparation of Ajuga nipponesis Makino, as recommended in folk medicine for the treatment of hepatoma. He developed profound gastrointestinal upset immediately, and decreasing urine output and bilateral leg edema over the following 2 days. Notable laboratory findings included elevated levels of blood urea nitrogen, creatine, bilirubin, and hepatic transaminases. Deterioration of renal function was noted during hospitalization and he died 11 days after ingesting the herbal preparation. Two other healthy individuals also consumed the same herbal preparation at the same time but developed only vomiting and diarrhea. One or more of the four major components of Ajuga nipponesis Makino may be responsible for the renal toxicity found in our patient.