Herbal Medicines Reported to Have Effects on Coagulation
| Herbal Medicine | Propsed Mechanism | Drug Interactions |
| Alfalfa | Contains coumarin constituents | ? |
| Angelica | Contains coumarin constituents | ? |
| Aniseed | Contains coumarin constituents | ? |
| Asafoetida | Contains coumarin constituents | ? |
| Celery | Contains coumarin constituents | ? |
| Chamomille | Contains coumarin constituents | Large doses may interfere with anticoagulant therapy |
| Clove | Inhibits platelet activity | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Dong Quai | ? | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Echinacea | ? | Increases bleeding time (but not INR) has been reported in patients on long-term warfarin therapy |
| Evening Primrose Oil | Inhibits platelet aggregation | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Feugreek | Contains coumarin constituents | ? |
| Fever Few | Inhibits platelet aggregation | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Garlic | Inhibits platelet aggregation | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Ginger | Inhibits platelet aggregation | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Gingko biloba | Inhibits platelet aggregation | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Ginseng, Panax | Inhibits platelet aggregation | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Goldenseal | ? | May interact with warfarin |
| Horse Chestnut | Contains coumarin constituents | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Kava Kava | Inhibits platelet aggregation | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Licorice | Inhibits platelet activity | May interact with anticoagulants or antiplatelet drugs to increase risk of bleeding |
| Meadowsweet | Contains salicylate constituents | Same precautions as with salicylates may be warranted |
| Poplar | Contains salicylate constituents | Same precautions as with salicylates may be warranted |
| Prickly Ash, Northern | Contains coumarin constituents | ? |
| Prickly Ash, Southern | Contains coumarin constituents | ? |
| Quassia | Contains coumarin constituents | ? |
| Red Clover | Contains coumarin constituents | ? |
| White Willow/Willow Bark | Contains salicylate constituents | Same precautions as with salicylates may be warranted |
Julie Golembiewski, Pharm. D., University of Michigan Health System

