Onion - Acetaminophen, Codeine Interaction
Herbal: Onion
Also Known As: Allium cepa, Allii Cepae Bulbus, Cebolla, Échalote, Green Onion, Jeju Steamed Onion, Oignon, Oignon Vert, Onions, Palandu, Piyaj, Shallot
Drug: Acetaminophen, Codeine
Brand names:
Tylenol w/ Codeine, Tylenol No.3
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Acetaminophen, Codeine is classified as belonging to the following category: Cytochrome P450 2E1 (Cyp2E1) Substrates
Theoretically, taking onion might increase the levels and clinical effects of drugs metabolized by CYP2E1.
Animal research shows that taking onion powder inhibits CYP2E1. However, this interaction 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
- Teyssier, C., Amiot, M. J., Mondy, N., Auger, J., Kahane, R., and Siess, M. H. Effect of onion consumption by rats on hepatic drug-metabolizing enzymes. Food Chem.Toxicol. 2001;39(10):981-987.
Onion Overview
Onion, a common vegetable, has a long history of use in traditional medicine. It is believed to have a number of health benefits due to its high content of antioxidants, such as quercetin, as well as its anti-inflammatory properties.
It is often used to treat respiratory conditions, such as colds and flu, due to its expectorant and decongestant effects. It is also believed to be helpful in relieving symptoms of asthma and bronchitis and is thought to have antimicrobial properties, making it useful for treating infections and wounds. Additionally, onion is believed to help lower cholesterol levels, reduce the risk of heart disease, and improve blood sugar control. Most dietary supplements containing onion are an extract that contains allicin.
Onion - More Interactions
Onion interacts with 272 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. |
Return to the main supplement interaction checker page
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.
Ask A Pharmacist About Your Herbal Questions!
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!
Ask A Pharmacist