Safflower & Warfarin

Publication Date: 
Tue, 10/01/2013
By: Alere Staff

Safflower, also known as American saffron, is used for a variety of conditions including cardiovascular disease and preventing atherosclerosis among other conditions.1 Safflower oil is used as cooking oil as well as dried and used to make tea.

Although low in vitamin K, safflower oil has been linked to prolonging bleeding time and therefore can increase INR test results.1, 2 Safflower’s use for medicinal purposes has not been evaluated by the U.S. Food and Drug Administration. Patients should consult their healthcare professionals before starting or stopping safflower and use safflower oil with caution during cooking.

Increasing testing frequency is also recommended when starting or stopping any new medication or dietary supplement including vitamins. To safely evaluate the effect of safflower oil on an INR test result, it can help to keep a diet consistent and use the Vitamin K Food Diary® Log.

Home INR monitoring may help improve your control of warfarin with more frequent testing. Studies have shown that increasing testing frequency with weekly testing of INR improves patient safety and helps keep the drug in its therapeutic effective zone.3,4 Weekly testing was shown to be the most effective testing frequency.3 Medicare and many private/commercial insurance reimburse patients for weekly patient self-testing.5 Go to the Getting Started page or call Alere at 1.800.504.4032 for more information about testing your INR at home.


  1. Therapeutic Research Faculty. Natural Medicines Comprehensive Database. 11th Edition. Stockton, CA: Therapeutic Research, 2009.
  2. McGuffin, Michael. Ed., Christopher Hobbs, Roy Upon, and Alicia Goldber. American Herbal Products Association’s Botanical Safety Handbook. Prepared for the Stndards Committee of the American Herbal Products Association. CRC Press LLC. 1997.
  3. Am J Manag Care. 2014;20(3):202-209.
  4. Heneghan C., et al. Self-monitoring of oral anticoagulation: a systematic review and meta-analysis. 2006. Lancet, 367, 404-11.
  5. Center for Medicare and Medicaid Services. Decision Memo for Prothrombin Time (INR) Monitor for Home Anticoagulation Management  (CAG-00087R) [Memorandum]. 2008. Baltimore, MD.