Health Guide


What is it?

Coumarin can be found in many plants including dong quai, red clover, sweet clover, and tonka bean. It is used mainly in the treatment of cancer and can also be used as a blood thinner.

Other names for coumarin include: 1,2-benzopyrone, tonka bean camphor, cumarin, kumaryna.

Ask your doctor, nurse, or pharmacist if you need more information about this medicine or if any information in this leaflet concerns you.

Before Using:

Tell your doctor if you

  • are taking medicine or are allergic to any medicine (prescription or over-the-counter (OTC) or dietary supplement)
  • are pregnant or plan to become pregnant while using this medicine
  • are breastfeeding
  • have any other health problems, such as high blood pressure or heart or blood vessel disease


Talk with your caregiver about how much coumarin you should take. The amount depends on the strength of the medicine and the reason you are taking Coumarin. If you are using this medicine without instructions from your caregiver, follow the directions on the medicine bottle. Do not take more medicine or take it more often than the directions tell you to.

To store this medicine:

Keep all medicine locked up and away from children. Store medicine away from heat and direct light. Do not store your medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down and not work the way it should work. Throw away medicine that is out of date or that you do not need. Never share your medicine with others.

Drug and Food Interactions: Coumarin may interact with other medicines you may be taking. Talk with your doctor, pharmacist, or nurse before taking coumarin with any other medicine.


  • Before taking coumarin, tell your doctor if you are pregnant or breastfeeding
  • If you have liver problems you should not take coumarin without first consulting your health care professional (2)

Side Effects:

Call your doctor right away if you have any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hand, swelling or tingling in your mouth or throat, chest tightness, trouble breathing, or rash.
  • Unusual bleeding or bruising (7)

Other Side Effects:

You may have the following side effects, but this medicine may also cause other side effects. Tell your doctor if you have side effects that you think are caused by this medicine.

  • Diarrhea, dizziness, upset stomach, vomiting (2)
  • Insomnia (sleeplessness) (2)


1. Berkarda B, Bouffard-Eyuboglu H & Derman U: The effect of coumarin derivatives on the immunological system of man. Agents Actions 1983;13:50-52.

2. Dexeus FH, Logothetis CJ, Sella A et al: Phase II study of coumarin and cimetidine in patients with metastatic renal carcinoma. J Clin Oncol 1992; 8:325-330.

3. Marshall ME, Butler K & Fried A: Phase I evaluation of coumarin (1,2-benzopryne) and cimetidine in patients with advanced malignancies. Mol Biother 1991; 3:170-178.

4. Marshall ME, Riley LK, Rhoades J et al: Effects of coumarin (1,2-benzopryne) and cimetidine on peripheral blood lymphocytes, natural killer cells, and monocytes in patients with advanced malignancies. J Biol Resp Mod 1989; 8(1):62-69.

5. Marshall ME, Mendelsohn L, Butler K et al: Treatment of metastatic renal cell carcinoma with coumarin (1,2-benzopryne) and cimetidine: a pilot study. J Clin Oncol 1987; 5(6):862-866.

6. Mohler JL, Gomella LG, Crawford D et al: Phase II evaluation of coumarin (1,2-Benzpyrone) in metastatic prostatic carcinoma. Prostate 1992; 20:123-131.

7. Product Information: Coumadin(R), warfarin. Bristol Myers Squibb, New York, NY, 2006.

Last Updated: 7/4/2018
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