Toxic hepatitis has been reported as a major cause of acute hepatitis, but its potential induction by herbal remedies and/or health foods is usually neglected. We experienced a case of toxic hepatitis associated with Polygoni multiflori, a Chinese herb commonly known as Ho-Shou-Wu. A 54-year-old woman consumed Ho-Shou-Wu for 1 month, after which she experienced fatigue and overall weakness. A diagnosis of toxic hepatitis was made based on her clinical history, the findings for viral markers and other laboratory data, and ultrasonography. Her condition improved considerably after she stopped taking Ho-Shou-Wu. However, she resumed taking Ho-Shou-Wu immediately after discharge from hospital, which aggravated her symptoms and liver function. She was immediately readmitted and stopped taking Ho-Shou-Wu. Her relapse into hepatitis immediate after resuming consumption of the herb is strongly indicative of the validity of Koch's postulate in this case.