Although there are no specific studies demonstrating interactions with anticoagulants, the following herbs contain coumarin-like substances that may interact with heparin and could conceivably cause bleeding. These herbs include dong quai, fenugreek, horse chestnut, red clover, sweet clover, and sweet woodruff. People should consult a healthcare professional if they’re taking an anticoagulant and wish to use one of these herbs.
- Miller LG, Murray WJ, eds. Herbal Medicinals: A Clinician's Guide. New York: Pharmaceutical Products Press, 1999, 313-5.