If you are taking Coumadin, a prescription blood thinner, it is important to monitor your herbs and herbal supplements. Many herbs and supplements interact with the drug and make it less effective. Because Coumadin works by decreasing Vitamin K activity, you must monitor the amount of Vitamin K in herbs you consume. Many herbs and herbal supplements are known to interfere with Coumadin, and should be avoided. Talk to your doctor or dietitian before adding any herbs or supplements to your diet.
Herbs to Avoid
Don't take or use herbs that contain more than 60 percent of the daily value of Vitamin K. This helps keep Vitamin K intake consistent, so it won't interfere with your Coumadin. Some herbs high in Vitamin K include parsley and endive. One cup of endive contains 70 percent of the daily value of Vitamin K; 1/4 cup of parsley contains 300 percent of the daily value of Vitamin K.
Safe Herbs
Herbs low in Vitamin K are not likely to interfere with Coumadin function. These include chives, dill and oregano. Additionally, it is safe to use most herbs for flavor in cooking. However, herbal supplements are much more potent than herbs used in cooking, and should be used with caution. Consult with your doctor or dietitian if you are concerned about use of herbs.
Herbal Supplements to Avoid
Many dietary and herbal supplements can interact with Coumadin. These include arnica, bilberry, butchers broom, cat's claw, dong quai, feverfew, forskolin, garlic, ginger, ginkgo, horse chestnut, insositol hexaphosphate, licorice, melilot (sweet clover), pau d'arco, red clover, St. John's wort, sweet woodruff, turmeric, willow bark and wheat grass. Avoid these dietary supplements, and consult with your doctor before beginning any other supplementation.
Herbs and Vitamin K
The most important thing to remember about taking herbal supplements on Coumadin is Vitamin K. Limit to one serving daily any herbs with more than 200 percent of the daily value of Vitamin K. Limit to three servings daily any herbs with 60 percent to 199 percent of the daily value. If your Vitamin K is consistent, Coumadin can work effectively to prevent harmful blood clots.
