Blood Thinners

Blood thinners are medications taken orally or intravenously to prevent a blood clot. Blood clots stop the flow of blood to the heart, lungs, or brain and can cause a heart attack or stroke.

What They Do

Some blood-thinning medications work by thinning the blood to prevent blood cells from sticking together in the veins and arteries. Others prevent blood clots by lengthening the amount of time it takes your blood to clot.

Your physician will monitor your dosage of anticoagulant carefully. He or she may periodically run a blood test called the prothrombin time test (PT) to measure your international normalized ratio (INR). INR is the rate at which your blood clots. An appropriate INR rate varies from person to person according to their medical history. However, keeping in your INR range can keep you from bleeding or clotting too easily.

Who Should Take Them

Those who have been diagnosed with different forms of heart disease, including heart valve disease and irregular heart rhythms, may be prescribed blood-thinning medications called anticoagulants. “Coagulate” used as a medical term means “to clot.” Common blood thinners include:

  • warfarin (Coumadin and Jantoven)
  • enoxaparin (Lovenox)
  • heparin (Hep-Lock)

Drug Interactions

While not all blood thinners are affected by the same substances, a number of foods, herbs, and medications can interact with blood-thinning medications. This can render the drug more or less effective than your dosage would suggest. Speak to your doctor regarding your specific medication and your diet.

Vitamin K

Vitamin K is a nutrient that can hamper the effects of some anticoagulants, such as warfarin. Depending on the particular medication you take, you may still be able to include low to moderate levels of vitamin K-rich foods in your diet. Examples of cruciferous vegetables and greens that contain moderate to high levels of vitamin K include:

  • cabbage
  • Brussels sprouts
  • broccoli
  • asparagus
  • endive
  • kale
  • lettuce
  • spinach
  • mustard greens
  • turnip greens
  • collard greens


Heart disease patients who take anticoagulant medications should use herbal supplements and teas with caution. Several herbs interfere with the anti-clotting activity of blood thinners and can increase bleeding time or your risk of bleeding. Consult your cardiologist or primary care physician before using any herbal supplement or tea, especially the following:

  • chamomile
  • echinacea
  • clove
  • evening primrose oil
  • dong quai
  • licorice
  • ginseng
  • gingko biloba
  • goldenseal
  • willow bark

Alcoholic beverages and cranberry juice can also be harmful when using blood thinners. Avoid these items as much as possible.


Prescription and over-the-counter medications should be taken with caution when using blood thinners. A variety of antibiotics, anti-fungal drugs, pain relievers, and acid reducers can increase your risk of bleeding. Other drugs, including birth control pills, can decrease the effects of anticoagulants and increase your risk of developing a blood clot. Notify your doctor of all the medications you’re taking to avoid a potentially harmful interaction.

Side Effects

Side effects of blood thinners may occur in some individuals. Bleeding is the most common reaction and can occur in a variety of ways, including:

  • heavy periods
  • bloody or discolored urine or feces
  • nosebleeds
  • bleeding gums
  • prolonged bleeding from a cut

Other side effects can include:

  • dizziness
  • muscle weakness
  • hair loss
  • rashes

The presence of blood thinners in your system can increase your risk of internal bleeding following an injury. Seek medical attention if you experience any of these side effects and you fall or bump your head—even if you don’t have external bleeding. Your doctor may prohibit you from participating in contact sports to reduce this risk, but that doesn’t mean you can’t exercise or live a normal life.

Discuss your exercise goals with your physician. Swimming, walking, and jogging are excellent forms of exercise and safe for most people taking anticoagulants. Protect yourself when using knives, scissors, or yard equipment. In order to avoid excessive bleeding during regularly scheduled cleanings, tell your dentist that you take blood thinners.

Natural Blood Thinners

Foods that you may eat and herbs that you may use for flavoring in your cooking can have natural anticoagulant properties. Garlic, ginger, celery seed, and aniseed all carry coumarin effects (meaning that they can prevent your blood from clotting).

Foods rich in vitamin E are also natural blood thinners. A number of oils—such as safflower, corn, olive, sunflower, soybean, and wheatgerm—contain vitamin E. Other foods sources of vitamin E include:

  • spinach
  • tomatoes
  • mangoes
  • kiwi
  • peanut butter
  • almonds
  • sunflower seeds
  • broccoli

Natural anticoagulants can be beneficial to your heart health, but should be consumed with caution. Check with your doctor before eating natural anticoagulants if you take blood-thinning medications to control your heart disease.