The short answer
Garlic supplements may add to bleeding concerns during dalteparin treatment, but the size of this interaction is uncertain. A small human study found no platelet effect from its tested commercial garlic product.
What this answer covers
Oral Allium sativum supplements with subcutaneous dalteparin sodium; food amounts, oils, aged extracts and other preparations are not identical.
- Supplement or preparation
- Allium sativum
- Medication ingredient
- dalteparin
The basis for the precaution
Federal garlic guidance cautions about bleeding with supplements, particularly with anticoagulants. Dalteparin’s label also warns about substances that impair platelet function. Together these support review of the combination without proving a dalteparin-specific bleeding rate.
Human findings are not uniform
Ten volunteers took several commercial herbs in separate periods, including garlic. After two weeks of each product, the platelet-function test showed no inhibition, while aspirin did. This small surrogate study did not test dalteparin or rule out rare clinical bleeding.
Preparation changes the question
The caution concerns supplemental exposure, which varies with processing and formulation. Usual culinary garlic is not automatically equivalent to a concentrated tablet. Bring the actual product label rather than assuming every garlic preparation has the same effect.
Timing is not established protection
No protective gap between garlic and dalteparin doses is established. Tell the dalteparin team about the exact supplement before starting or changing it. Report unusual bleeding or bruising promptly; serious bleeding, black stools or vomiting blood needs urgent assessment. Do not change prescribed dalteparin yourself.
Evidence and practical considerations
Side effects & toxicity
Indirect supplement and anticoagulant precaution, with source-specific null findings and no quantified dalteparin co-use risk.
- Exact scope
- Oral Allium sativum supplements with subcutaneous dalteparin sodium; food amounts, oils, aged extracts and other preparations are not identical. with Subcutaneous dalteparin sodium; active ingredient bridge to RxCUI67109 IN. Not UFH or another LMWH.
- Medication form and route
- subcutaneous dalteparin; oral supplement
What remains uncertain
- Source-specific population, preparation and endpoint limits apply; no universal dose or timing rule.
Factors that may matter: Exact preparation; Dose and duration; Kidney function; Other medicines.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients receiving subcutaneous dalteparin sodium.
Bleeding risk can increase with platelet inhibitors and other anticoagulants. Hyperkalemia is listed among postmarketing reports, whose frequency and causal relationship cannot reliably be established.
How this applies: Exact dalteparin sodium injection product and route; no silent transfer of unfractionated-heparin dosing or monitoring rules.
Does not specifically name these supplements. Not unfractionated heparin, another LMWH, an oral anticoagulant or topical therapy.
Source 2: regulatory guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: Users of the specified preparation.
Garlic supplements may increase bleeding risk; particular attention advised around surgery and with anticoagulants.
How this applies: Exact species, preparation, route and measured endpoints govern applicability; other anticoagulants are not silently treated as dalteparin.
Guidance does not quantify dalteparin-specific bleeding or imply that usual food amounts equal a concentrated supplement.
Source 3: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Ten adult volunteers.
No PFA-100 platelet-function effect from any tested herb; aspirin control inhibited function.
How this applies: Exact species, preparation, route and measured endpoints govern applicability; other anticoagulants are not silently treated as dalteparin.
Only ten volunteers and a laboratory platelet test. Not clinical bleeding surveillance in dalteparin recipients; original experimental component used, not the accompanying review.
Research assessment: · Open full citations ↗
Timing & monitoring
No universal avoidance or protective spacing interval established; individual product and bleeding-risk review is appropriate.
- Exact scope
- Oral Allium sativum supplements with subcutaneous dalteparin sodium; food amounts, oils, aged extracts and other preparations are not identical. with Subcutaneous dalteparin sodium; active ingredient bridge to RxCUI67109 IN. Not UFH or another LMWH.
- Medication form and route
- subcutaneous dalteparin; oral supplement
What remains uncertain
- Source-specific population, preparation and endpoint limits apply; no universal dose or timing rule.
Factors that may matter: Exact preparation; Dose and duration; Kidney function; Other medicines.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients receiving subcutaneous dalteparin sodium.
Bleeding risk can increase with platelet inhibitors and other anticoagulants. Hyperkalemia is listed among postmarketing reports, whose frequency and causal relationship cannot reliably be established.
How this applies: Exact dalteparin sodium injection product and route; no silent transfer of unfractionated-heparin dosing or monitoring rules.
Does not specifically name these supplements. Not unfractionated heparin, another LMWH, an oral anticoagulant or topical therapy.
Source 2: regulatory guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: Users of the specified preparation.
Garlic supplements may increase bleeding risk; particular attention advised around surgery and with anticoagulants.
How this applies: Exact species, preparation, route and measured endpoints govern applicability; other anticoagulants are not silently treated as dalteparin.
Guidance does not quantify dalteparin-specific bleeding or imply that usual food amounts equal a concentrated supplement.
Source 3: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Ten adult volunteers.
No PFA-100 platelet-function effect from any tested herb; aspirin control inhibited function.
How this applies: Exact species, preparation, route and measured endpoints govern applicability; other anticoagulants are not silently treated as dalteparin.
Only ten volunteers and a laboratory platelet test. Not clinical bleeding surveillance in dalteparin recipients; original experimental component used, not the accompanying review.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Prepared exact dalteparin article with independently checked product label and explicit limits on indirect supplement evidence. | |
| Research summary published |
Article revision: 3fb656e05599de91
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.