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Source: Krames StayWell

Diet Guidelines for Patients Taking Warfarin (Coumadin)

The foods you eat and drink can affect how your medicine works. Here is what you should know about warfarin and your diet.

Vitamin K in foods

While you are on warfarin, your intake of vitamin K should stay the same from day to day. Your warfarin dose is based on your daily intake of vitamin K foods. So it is important to get the same amount of vitamin K each day.

Warfarin helps to thin your blood. Vitamin K helps to clot your blood. When there is a sudden increase or decrease in vitamin K intake, the warfarin may not work as well.

If you ate vitamin K foods before starting warfarin, you should continue to eat them. If you plan to eat more or less of the vitamin K foods, you must see your doctor. Your doctor will change your dose to match your vitamin K intake.

Dietary supplements

Some dietary supplements have vitamin K. We do not know how these interact with warfarin. To be safe, don't take dietary supplements (including your daily multi-vitamin) unless your doctor approves.

Vitamin E and fish oil are often taken by people with heart problems. Both of these have blood-thinning effects. If you take these, be sure to tell your doctor.

These foods are high in vitamin K

(serving size is ½ cup)

These foods are medium-high in Vitamin K

(serving size is 1 cup, except brussels sprouts = ½ cup)

Collards (cooked)

Brussels sprouts (cooked)

Kale (cooked)


Mustard greens (cooked)

Endive (raw)

Parsley (raw)

Green leaf lettuce

Spinach (cooked)

Romaine lettuce

Swiss chard (cooked)

Spinach (raw)

Turnip greens (cooked)

Turnip greens (raw)


If you choose to drink, have no more than 1 to 2 drinks in 24 hours. One drink equals:

  • 5 ounces of wine

  • 12 ounces of beer

  • 1 1/2 ounces of hard liquor

Drinking too much alcohol will increase your risk for bleeding. Ask your doctor how much alcohol is safe for you. Some doctors advise no alcohol while taking warfarin.

Cranberry juice

You may wish to limit how much cranberry juice you drink each day.

The makers of warfarin state that cranberry juice may increase your risk of bleeding. Studies do not support this. If you have questions about cranberry juice, please speak with your doctor or pharmacist.

Green tea

Green tea is often found on lists of foods that are high in Vitamin K. The tea leaves themselves are high in Vitamin K, but the tea provides only a small amount. You can drink a couple cups of green tea—just do not drink gallons of it.


American Dietetic Association. ADA Nutrition Care Manual. Available at Accessed 2005.

Bristol-Myers Squibb Co. Patient's Guide to Using Coumadin, Princeton, NJ: 2003.

National Institute of Health. Drug-nutrient interactions: Coumadin (warfarin) and vitamin K. Last updated: December 2003. Accessed October 2006.

USDA, Human Nutrition Information Service. Provisional table on the vitamin K content of foods. HNIS/PT-104. Revised 1994.

For informational purposes only. Not to replace the advice of your health care provider.
Copyright © 2006 Fairview Health Services. All rights reserved. SMARTworks 520536 – REV 09/15.

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