Herbs or natural products that may cause cancer and harm part four of a four-part series.

PURPOSE/OBJECTIVES To provide evidence-based research information about 27 herbs and natural products that have the potential to cause cancer and harm. DATA SOURCES Natural Medicines Comprehensive Database and Lawrence Review of Natural Products Monograph System. Information about these herbs has been found in evidence-based studies cited in the references. DATA SYNTHESIS Early research shows that some herbs and natural products appear to have the potential to cause cancer and harm. Oncology nurses who receive this information can become resources for patients and other healthcare professionals. CONCLUSIONS Consumers and healthcare professionals are wise to weigh the benefits or risks and possibly limit or avoid the use of these products. IMPLICATIONS FOR NURSING The table and text in this article are presented as quick resources for healthcare professionals working in clinical oncology.