The short answer
The added bleeding risk from garlic supplements with diflunisal is uncertain. Review the exact supplement with your prescriber, especially if you have ulcer or bleeding risk factors.
What this answer covers
Oral garlic supplements products with prescription oral diflunisal. Exact preparation, dose and duration matter; other drugs and food exposures are not interchangeable.
- Supplement or preparation
- Allium sativum
- Medication ingredient
- diflunisal
What the human evidence shows
A study of one garlic tablet product found no significant platelet aggregation change, but participants reported menstrual or nasal bleeding. Aspirin had been stopped before the garlic phase, and NSAIDs were excluded. It therefore raises a product safety concern without measuring what happens when garlic is combined with diflunisal.
Diflunisal differs from aspirin
The diflunisal label describes a reversible, dose-dependent platelet effect. In short studies, 250 mg twice daily had no measurable effect and 500 mg twice daily had a slight effect. These findings do not remove its serious GI bleeding warning or make aspirin studies a direct test of this combination.
Review the exact product
Bring the product label and daily amount. Government guidance cautions that garlic supplements may increase bleeding risk, particularly with medicines that affect bleeding. Culinary garlic is a different exposure from the concentrated tablets studied; the evidence does not justify a blanket restriction on garlic in meals.
Recognize the medicine’s own warning signs
Diflunisal can cause serious stomach or intestinal bleeding even without a supplement. Seek urgent care for vomiting blood or black, tarry stools, and report persistent stomach pain or unusual bleeding. A few hours of separation has not been shown to prevent a combined bleeding effect. Tell your prescriber about other pain relievers, aspirin and anticoagulants.
Evidence and practical considerations
Side effects & toxicity
An increased bleeding or gastrointestinal-injury rate specifically from garlic supplements with diflunisal has not been established.
- Exact scope
- Oral garlic supplements products with prescription oral diflunisal. Exact preparation, dose and duration matter; other drugs and food exposures are not interchangeable. with Exact diflunisal RxCUI 3393 IN, confirmed by current RxNorm. Prescription oral tablets; not aspirin, and not a class-average NSAID effect.
- Medication form and route
- Oral
What remains uncertain
- Small, short or other-drug studies do not establish this exact combination’s risk or rule out rare serious bleeding.
Factors that may matter: Exact preparation and dose; Fasting versus fed dosing; Bleeding and ulcer history; Other medicines.
Read the supporting source summaries
Source 1: Current prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Prescription oral diflunisal users and healthy-volunteer pharmacology studies.
Diflunisal has dose-dependent reversible platelet effects. At 500 mg twice daily effects were slight; 250 mg twice daily had no measurable effect in a short study. Serious GI bleeding and ulcers remain labeled risks. Antacids may lower levels, especially with continuous use.
How this applies: Exact current drug label. Exact diflunisal RxCUI 3393 IN, confirmed by current RxNorm. Prescription oral tablets; not aspirin, and not a class-average NSAID effect.
Not proof of each supplement combination. Short healthy-volunteer fecal blood-loss findings do not establish long-term GI safety. Aspirin has different platelet pharmacology. No universal antacid separation interval.
Source 2: Original clinical research
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 62 healthy adults aged 20-50.
No significant platelet aggregation change with garlic; menstrual and nasal bleeding were reported.
How this applies: Exact drug where specified; other-drug and supplement-only findings remain indirect.
Open label, single product and inconsistent reported denominators. No concomitant diflunisal or aspirin; laboratory null result does not negate reported bleeding or quantify combination risk.
Source 3: Medication terminology
rxnav.nlm.nih.gov · Source check Sep 10, 2026
Population: Terminology record.
Diflunisal, IN.
How this applies: Exact identity.
No clinical evidence.
Research assessment: · Open full citations ↗
Side effects & toxicity
Garlic supplement use warrants review alongside diflunisal, especially with other bleeding risks.
- Exact scope
- Oral garlic supplements products with prescription oral diflunisal. Exact preparation, dose and duration matter; other drugs and food exposures are not interchangeable. with Exact diflunisal RxCUI 3393 IN, confirmed by current RxNorm. Prescription oral tablets; not aspirin, and not a class-average NSAID effect.
- Medication form and route
- Oral
What remains uncertain
- A precaution based on defined supplement evidence and the exact drug label, not a measured combination event rate.
Factors that may matter: Exact preparation and dose; Fasting versus fed dosing; Bleeding and ulcer history; Other medicines.
Read the supporting source summaries
Source 1: Current prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Prescription oral diflunisal users and healthy-volunteer pharmacology studies.
Diflunisal has dose-dependent reversible platelet effects. At 500 mg twice daily effects were slight; 250 mg twice daily had no measurable effect in a short study. Serious GI bleeding and ulcers remain labeled risks. Antacids may lower levels, especially with continuous use.
How this applies: Exact current drug label. Exact diflunisal RxCUI 3393 IN, confirmed by current RxNorm. Prescription oral tablets; not aspirin, and not a class-average NSAID effect.
Not proof of each supplement combination. Short healthy-volunteer fecal blood-loss findings do not establish long-term GI safety. Aspirin has different platelet pharmacology. No universal antacid separation interval.
Source 2: Government supplement guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: Garlic supplement users.
Warns of possible bleeding risk, particularly with medicines affecting bleeding and around surgery.
How this applies: Supplement precaution alongside exact prescription NSAID context.
Guidance does not quantify a diflunisal combination risk or establish GI ulceration.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Sources checked and article drafted. | |
| Research summary published |
Article revision: 06bb06d6e7152fcb
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.