Fennel - Aspirin, Omeprazole Interaction
Herbal: Fennel
Also Known As: Foeniculum vulgare, Adas, Almindelig fennikel, Arapsaci, Badian, Badishep, Bari-Sanuf, Bisbas, Bitterfenchel, Bitter Fennel, Carosella, Common Fennel, Dunkler Fenchel, Endro, Erva-doce, Fänkål, Fenchel, Fenchle, Fenkuł, Fennel Essential Oil, Fennel Oil, Fennel Seed, Fenneru
Drug: Aspirin, Omeprazole
Brand names:
Yosprala
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Aspirin, Omeprazole is classified as belonging to the following category: Cytochrome P450 3A4 (Cyp3A4) Substrates
Theoretically, fennel might increase levels of drugs metabolized by CYP3A4.
In vitro research suggests that fennel inhibits CYP3A4 enzyme activity. This effect has not been reported in humans.
Interaction Rating
Likelihood of Occurrence
PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
References
- Subehan, Usia, T., Iwata, H., Kadota, S., and Tezuka, Y. Mechanism-based inhibition of CYP3A4 and CYP2D6 by Indonesian medicinal plants. J Ethnopharmacol. 5-24-2006;105(3):449-455.
- Subehan, Zaidi, S. F., Kadota, S., and Tezuka, Y. Inhibition on human liver cytochrome P450 3A4 by constituents of fennel (Foeniculum vulgare): identification and characterization of a mechanism-based inactivator. J Agric.Food Chem. 12-12-2007;55(25):101
Interaction Details
Aspirin, Omeprazole is classified as belonging to the following category: Anticoagulant/Antiplatelet Drugs
Theoretically, fennel might increase the risk of bleeding when used with antiplatelet or anticoagulant drugs.
Animal research suggests that fennel oil has antithrombotic and antiplatelet effects.
Interaction Rating
Likelihood of Occurrence
PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
References
- Tognolini, M., Ballabeni, V., Bertoni, S., Bruni, R., Impicciatore, M., and Barocelli, E. Protective effect of Foeniculum vulgare essential oil and anethole in an experimental model of thrombosis. Pharmacol.Res 2007;56(3):254-260.
- Tognolini, M., Barocelli, E., Ballabeni, V., Bruni, R., Bianchi, A., Chiavarini, M., and Impicciatore, M. Comparative screening of plant essential oils: phenylpropanoid moiety as basic core for antiplatelet activity. Life Sci. 2-23-2006;78(13):1419-1432.
Fennel Overview
Fennel is a plant species in the carrot family and native to the Mediterranean region. Fennell seeds are often used as a spice, and other parts as food.
Fennel has a distinctive, sweet, licorice-like flavor and is often used in cooking to add flavor to dishes such as sauces, salads, and baked goods. It is used in traditional medicine as a good source of vitamins and minerals, such as potassium, beta-carotene and vitamin C. It has also been used to treat a variety of conditions, including digestive issues, respiratory problems, and skin conditions.
Aspirin, Omeprazole Overview
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The combination of aspirin and omeprazole is used to reduce the risk of stroke or heart attack in patients who have had or are at risk of these conditions and are also at risk of developing a stomach ulcer when taking aspirin. Aspirin is in a class of medications called antiplatelet agents. It works by preventing platelets (a type of blood cell) from collecting and forming clots that may cause a heart attack or stroke. Omeprazole is in a class of medications called proton-pump inhibitors. It works by decreasing the amount of acid made in the stomach.
Fennel - More Interactions
Fennel interacts with 718 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
| Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
| Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
| Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
| Unknown | No interactions have been reported or no interaction data is currently available. |
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Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Drug descriptions are provided by MedlinePlus.
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Dr. Brian Staiger, PharmD
In addition to being a clinical pharmacist specializing in pharmacotherapy, Dr. Brian Staiger is a registered herbalist through the American Herbalist Guild. He has combined his passion for pharmacy practice with the study of medical ethnobotany to improve patient care. Feel free to reach out about any of your herbal or medication questions!
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