Warfarin (Coumadin) Interactions with Food and HerbsVitamin K Rich Foods: Vegetables like broccoli, cabbage, coriander, collard greens, spinach, kale, black licorice, turnip greens, Brussels sprouts and avocados which are rich in vitamin K decrease the ability of warfarin to prevent blood clotting. Intake of soy foods may increase or decrease warfarin effect.
Grapefruit : Avoid eating grapefruit or drinking grapefruit juice with warfarin as it decreases the body's ability to metabolize the drug.
Cranberry Fruit and Juice :Do not drink cranberry juice while on warfarin as it increases the anticoagulant effect of the drug.
Others: Glucosamine, fish oils, flaxseed oils interact with warfarin and increase bleeding. Eating chargrilled foods decreases warfarin activity and cooked onions increase warfarin activity.
Herbs: Do not take garlic, ginger, ginseng, ginkgo, cannabis, dong quai (Angelica sinesis), fenugreek, thyme, oregano, dried basil, alfa alfa with warfarin as these herbs when taken with warfarin increase the risk of bleeding.
Parsley and passion flower increase the effect of the warfarin therapy while St. John's wort reduces the effect of the drug.