Based on NIH | Is it safe to take omeprazole if I use garlic daily, and are there any interactions or risks to be aware of?

Most people can use omeprazole and garlic together safely, but there are a few potential interactions and risks worth considering. The main concerns are that garlic supplements may change how omeprazole is metabolized in some people and that garlic can increase bleeding tendency, which may matter if you also take blood thinners or certain other drugs. If you use high‑dose garlic supplements (not just food amounts), monitoring and a quick medication review are sensible. ^{[1] [2]}

What we know about interactions

• Metabolism interaction (CYP2C19): Omeprazole is broken down largely by an enzyme called CYP2C19. Garlic’s active compound allicin has been shown in a small human study to inhibit CYP2C19, which increased omeprazole blood levels by roughly 50–70% in people with certain common genotypes. This did not appear to affect CYP3A4. This suggests garlic supplements could raise omeprazole exposure in some individuals, potentially increasing effects or side effects like headache or stomach upset. ^[1]
• General omeprazole interaction profile: Omeprazole can affect other drugs via CYP2C19 inhibition and by raising stomach pH, and labels advise telling your clinician about all vitamins and herbal supplements. Clinically important interactions are well documented with clopidogrel, methotrexate (high dose), St. John’s wort, and rifampin; garlic is not specifically listed on labels, but disclosure of herb use is recommended. ^{[3] [4]}
• Clopidogrel caution (indirect relevance): Omeprazole can reduce activation of clopidogrel, lowering its antiplatelet effect. If you take clopidogrel, clinicians often avoid pairing it with omeprazole or switch to another stomach acid medicine. Garlic’s own antiplatelet effects could theoretically complicate bleeding/clotting balance in this setting. ^{[5] [6]}

Garlic and bleeding risk

• Antiplatelet effect: Garlic (especially in supplement form) can reduce platelet aggregation and has been linked to increased bleeding/bruising, particularly when combined with anticoagulants or antiplatelet drugs. Clinical guidance commonly advises stopping garlic supplements 1–2 weeks before surgery to reduce bleeding risk. ^[2]
• What this means with omeprazole: Omeprazole itself is not a blood thinner and does not increase bleeding risk materially by itself. However, if you also use drugs like warfarin or antiplatelets, adding garlic may raise bleeding risk, while omeprazole may alter other drug exposures so a full medication check is important. ^{[2] [5]}

Practical safety guidance

• Food vs. supplement doses: Typical culinary garlic in food is less likely to cause interactions. Most concerns come from concentrated garlic supplements (e.g., standardized allicin or aged garlic extract) taken daily. ^{[7] [2]}
• Watch for side effects: If you add or increase garlic supplements while on omeprazole, watch for increased omeprazole side effects (e.g., headache, abdominal symptoms) that could reflect higher drug levels. ^{[1] [3]}
• Tell your clinician about all herbs: Omeprazole labeling advises informing your clinician about all vitamins and herbal products because they can affect how medicines work. This is especially important if you also take clopidogrel, methotrexate (high dose), antiretrovirals, antifungals, or seizure medicines. ^{[3] [8]}
• Before procedures: If you have an upcoming surgery, dental extraction, or invasive procedure, consider pausing garlic supplements 1–2 weeks beforehand to lower bleeding risk, after discussing with your clinician. ^[2]

Who should be extra careful

• On blood thinners/antiplatelets: If you use warfarin, DOACs (e.g., apixaban), aspirin, or clopidogrel, garlic can increase bleeding tendency, and omeprazole can interact with clopidogrel’s activation. Medical review is recommended to balance stomach protection with clotting control. ^{[2] [5]}
• On drugs sensitive to CYP2C19: Because omeprazole and possibly garlic can affect CYP2C19, people on other CYP2C19‑substrate medicines may need closer monitoring. ^{[8] [9]}
• Undergoing surgery: Stop garlic supplements ahead of time as noted. Your surgical team should know about both omeprazole and garlic use. ^[2]

Bottom line

• Using omeprazole with culinary garlic is generally considered low risk. ^[7]
• Using omeprazole with daily garlic supplements may increase omeprazole levels in some people and can add bleeding risk if you’re also on blood thinners. A medication and supplement review with your clinician or pharmacist is a good idea, especially if you take clopidogrel, warfarin, other anticoagulants, or high‑dose methotrexate. ^{[1] [2] [5] [3]}

Quick reference: Key points

• Omeprazole + garlic supplements: possible ↑ omeprazole exposure via CYP2C19 inhibition (individual variability). ^[1]
• Garlic supplements: can increase bleeding; stop 1–2 weeks pre‑procedure. ^[2]
• Omeprazole: notable interactions include clopidogrel, methotrexate (high dose), St. John’s wort, rifampin always disclose herb use. ^{[3] [4]}

If you’d like, I can help review your exact garlic supplement brand and dose alongside your current medications to personalize the advice.