Heparin Injection and Chamomile: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Heparin Injection
Chamomile
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased risk of bleeding
Interaction Deep Dive
Theoretically, coumarins present in chamomile may potentiate the effect of anticoagulants241. Scopoletin-7-glucoside is a coumarin present in Roman chamomile, while umbelliferone, another coumarin, has been isolated from German chamomile 3. A case report described multiple internal hemorrhages in a 70-year-old woman following concomitant use of warfarin and chamomile 5. Caution is advised.
Why it happens (mechanism)
Additive anticoagulant effect
Literature reports
1 report — tap to read
a) A case report described multiple internal hemorrhages in a 70-year-old woman following concomitant use of warfarin and Matricaria chamommilla (chamomile). The patient had a history of mechanical mitral valve placement and atrial fibrillation and her medications included warfarin (stable dose of 4 mg 3 days/wk, 6 mg 4 days/wk for 11 months), amiodarone (taken concurrently with warfarin for 3 years), digoxin, synthroid, alendronate, metoprolol, and calcium-vitamin D. Five days prior to current presentation, the patient was diagnosed with an upper respiratory tract infection but was discharged without antibiotics. At that time, she had a hemoglobin level of 117 g/L, platelet count of 193 X 109 /L, and an INR of 3.6 (therapeutic range, 2.5 to 3.5). After discharge, she experienced pedal edema and used a chamomile-based skin lotion 4 to 5 times per day in an attempt to relieve it. In addition, she drank 4 to 5 cups of chamomile tea per day to soothe her sore throat. The patient claimed that she usually used both chamomile products once or twice daily. Five days post-discharge, she presented with shortness of breath on exertion, bilateral pedal edema, and had bruising in her perineal area, across her lower abdomen, and over her left hip. A complete blood count revealed a hemoglobin concentration of 80 g/L, platelet counts of 218 X 109/L, and an INR of 7.9. A CT scan revealed retroperitoneal hematoma in the pelvis and bilateral rectal muscle bleeding. The patient received 3 units of red blood cells and 2 units of plasma, and coagulation status was maintained using IV heparin therapy. The hemorrhages ultimately dissipated, heparin was discontinued, and warfarin dose was adjusted to achieve a stable INR of 2.5. It was postulated that the coumarin constituents of chamomile may have resulted in an additive anticoagulation effect 5.
Common questions
Can I take Heparin Injection and Chamomile together?
Increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.
How serious is the Heparin Injection and Chamomile interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Heparin Injection or Chamomile need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (5)
- Heck AM, DeWitt BA, & Lukes AL: Potential interactions between alternative therapies and warfarin. Am J Health Syst Pharm 2000; 57(13):1221-1227. DOI
- Norred CL & Brinker F: Potential coagulation effects of preoperative complementary and alternative medicines. Alt Ther 2001; 7(6):58-67.
- Newall CA, Anderson LA, & Phillipson JDNewall CA, Anderson LA, & Phillipson JD: Herbal Medicines: A Guide for Healthcare Professionals, The Pharmaceutical Press, London, England, 1996.
- Ernst E: Possible interactions between synthetic and herbal medicinial products. Part I: a systematic review of the evidence. Perfusion 2000; 13:4-15.
- Segal R & Pilote L: Warfarin interaction with Matricaria chamomilla. CMAJ 2006; 174(9):1281-1282. DOI
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