Danshen (Salvia Miltiorrhiza): Traditional Use, Research and Warfarin Interaction Reports

Danshen is the dried root and rhizome of Salvia miltiorrhiza. [1] It is used in China in several finished products, including pills and injections. If you take warfarin or another blood thinner, read the safety section first.

Urgent first: blood thinners

Case reports describe gross over-thinning of the blood and bleeding in people on long-term warfarin who also took danshen. A literature review found three such published cases and concluded that danshen should be avoided by people taking warfarin. [1] Do not change your warfarin plan on your own. Tell your prescriber and pharmacist about every herb and patent medicine. Seek urgent medical care for serious or unusual bleeding. In the US, Poison Help is 1-800-222-1222 and emergencies are 911.

Traditional use

In Chinese medicine danshen is placed among herbs that "promote blood circulation and remove blood stasis". [2] "Blood stasis" is a traditional idea, not a finding on a scan. In China danshen is commonly used for atherosclerosis-related disorders, meaning heart and brain blood vessel problems. [1] See How Chinese herbs are classified.

Forms

Danshen is the basis of "dripping pills", including Compound Danshen Dripping Pill, studied in the trials below. [3] Danshen is also an ingredient of Chinese herbal injections for heart and brain blood vessel disease. [2] Those injections go straight into the bloodstream and the review notes this may produce new effects or adverse reactions. [2] They are not consumer products and are outside this page's scope.

What research shows

The authors of the large meta-analysis found a high risk of bias in how trials were randomized and blinded and rated confidence as low. [4] See How to read a TCM study. Chest pain, shortness of breath or fainting needs emergency care, not an herb.

Warfarin, aspirin and other blood thinners

• Case reports and reviews: Reviews describe enhanced anticoagulation and bleeding when long-term warfarin users also took danshen. [6]
• How it may happen (proposed): the 2001 review lists several possible routes: effects on platelets and clotting, plus rat data showing danshen raised warfarin levels. [1] These are proposed mechanisms, and rat results do not directly predict people.
• Human pilot study: in 14 healthy volunteers, a danshen and kudzu (Gegen) combination changed how aspirin and warfarin were handled and affected clotting-related measures. [7] It was small and short and tested a two-herb product.
• Clopidogrel: a review of interactions between clopidogrel and TCM reports that danshen decreased platelet inhibition and lowered levels of clopidogrel's active metabolite in studies. [8]

The reviews also say evidence quality varies, with some herbs giving inconsistent results across experiments and clinical studies. [9] That uncertainty is a reason for caution, not for reassurance. See Chinese herbs and prescription medicines and Telling your doctor about TCM use.

Other cautions

• Before surgery or dental work, tell the team about danshen. See Chinese herbs before and after surgery.
• Pregnancy, breastfeeding and children: I did not find a source I could read, so no advice can be given beyond asking a clinician. See TCM in pregnancy.
• Quality: NCCIH reports that some Chinese herbal products have been contaminated with toxic compounds, heavy metals, pesticides and microorganisms. [10] See Chinese herbal products: quality and interactions.