Drug & supplement interaction

Green Tea + Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine

Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine brand name: Anatuss.

Moderate Interaction
Medically reviewed by · Updated October 2026
The bottom line Moderate

Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine falls into 4 drug categories that Green Tea can interact with; the most serious is rated moderate. Theoretically, concomitant use might have additive adverse hepatotoxic effects.

Read the full interaction report
SeverityModerate
LikelihoodUnlikely
Interactions4
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Green Tea and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine

These two interact in 4 distinct ways. Each one is explained separately below.

Why Are There 4 Interactions?

Green Tea interacts with whole categories of medication. Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine falls into 4 of those categories, so it can interact with Green Tea in 4 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

HEPATOTOXIC DRUGS

1 of 4

Why this applies to Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine

Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine falls under HEPATOTOXIC DRUGS — the group Green Tea interacts with.

Theoretically, concomitant use might have additive adverse hepatotoxic effects.
Green tea extract supplements have been linked to several cases of hepatotoxicity and might have additive hepatotoxic effects with other drugs..
Severity Moderate Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Anatuss is a combination cold and cough product, and the ingredient worth talking about here is the acetaminophen (the same pain and fever reducer found in Tylenol). Acetaminophen is processed by your liver, and in high doses it can stress that organ. Concentrated green tea extract supplements have, in rare cases, also been tied to liver trouble. So the concern is that the two together could add a little extra strain on your liver.

To be honest, this is mostly theoretical and based only on scattered case reports, so it's considered unlikely. Drinking regular green tea as a beverage is not the worry, high-dose extract capsules are. Just don't double up on acetaminophen from other products, and check with your pharmacist if you take green tea supplements or have any liver concerns.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bonkovsky HL. Hepatotoxicity associated with supplements containing Chinese green tea (Camellia sinensis). Ann Intern Med 2006;144:68-71.
  2. Gloro R, Hourmand-Ollivier I, Mosquet B, et al. Fulminant hepatitis during self-medication with hydroalcoholic extract of green tea. Eur J Gastroenterol Hepatol 2005;17:1135-7. PubMed
  3. Jimenez-Saenz M, Martinez-Sanchez, MDC. Acute hepatitis associated with the use of green tea infusions. J Hepatol 2006;44:616-9. PubMed
  4. Javaid, A. and Bonkovsky, H. L. Hepatotoxicity due to extracts of Chinese green tea (Camellia sinensis): a growing concern. J Hepatol 2006;45(2):334-335. PubMed
  5. Martinez-Sierra, C., Rendon, Unceta P., and Martin, Herrera L. [Acute hepatitis after green tea ingestion]. Med Clin (Barc.) 6-17-2006;127(3):119.
  6. Molinari, M., Watt, K. D., Kruszyna, T., Nelson, R., Walsh, M., Huang, W. Y., Nashan, B., and Peltekian, K. Acute liver failure induced by green tea extracts: case report and review of the literature. Liver Transpl. 2006;12(12):1892-1895. PubMed
  7. Federico, A., Tiso, A., and Loguercio, C. A case of hepatotoxicity caused by green tea. Free Radic.Biol Med 8-1-2007;43(3):474. PubMed
  8. Sarma, D. N., Barrett, M. L., Chavez, M. L., Gardiner, P., Ko, R., Mahady, G. B., Marles, R. J., Pellicore, L. S., Giancaspro, G. I., and Low, Dog T. Safety of green tea extracts : a systematic review by the US Pharmacopeia. Drug Saf 2008;31(6):469-484. PubMed
  9. Rohde, J., Jacobsen, C., and Kromann-Andersen, H. [Toxic hepatitis triggered by green tea]. Ugeskr.Laeger 1-17-2011;173(3):205-206.
  10. Yellapu, R. K., Mittal, V., Grewal, P., Fiel, M., and Schiano, T. Acute liver failure caused by 'fat burners' and dietary supplements: a case report and literature review. Can.J.Gastroenterol. 2011;25(3):157-160. PubMed
  11. Health Canada. Health Product Info Watch. October 2016; 5-6. Available at: http://www.hc-sc.gc.ca/dhp-mps/medeff/bulletin/hpiw-ivps_2016-10-eng.php#a15.
  12. Oketch-Rabah HA, Roe AL, Rider CV, et al. United States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extracts. Toxicol Rep. 2020;7:386-402. PubMed
  13. Pochet S, Lechon AS, Lescrainier C, et al. Herb-anticancer drug interactions in real life based on VigiBase, the WHO global database. Sci Rep 2022;12(1):14178. PubMed
Moderate

STIMULANT DRUGS

2 of 4

Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine also falls under STIMULANT DRUGS.

Theoretically, concomitant use might increase stimulant adverse effects.
Green tea contains caffeine. Due to the central nervous system (CNS) stimulant effects of caffeine, concomitant use with stimulant drugs can increase the risk of adverse effects.
Severity Moderate Likelihood Probable Evidence C

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

This combo cold product (Anatuss) contains phenylpropanolamine, a decongestant that acts as a stimulant on your body. Green tea naturally contains caffeine, which is also a mild stimulant. Putting two stimulant-type ingredients together can add up. The concern here is mostly theoretical and based on expert opinion, not strong studies, so don't panic.

In practice, you might just notice more of the jittery side effects: a faster or pounding heartbeat, feeling restless or wired, trouble sleeping, or a slight bump in blood pressure. A normal cup or two of green tea is unlikely to cause much. Concentrated green tea extract pills, which pack more caffeine, are more likely to stack the effect. If you have high blood pressure or heart concerns, check with your pharmacist before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Institute of Medicine. Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Washington, DC: National Academy Press, 2001. Available at: http://books.nap.edu/books/0309082587/html/index.html. DOI
Moderate

PHENYLPROPANOLAMINE

3 of 4

Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine also falls under PHENYLPROPANOLAMINE.

Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.
Green tea contains caffeine. Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure. Phenylpropanolamine also seems to increase caffeine serum levels.
Severity Moderate Likelihood Probable Evidence B

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

This combination cold and cough product (Anatuss) contains phenylpharmacy decongestant phenylpropanolamine, which can nudge your blood pressure up on its own. Green tea naturally carries caffeine, and pairing the two can have an additive effect, pushing blood pressure a bit higher. There's also a twist: phenylpropanolamine seems to slow how your body clears caffeine, so the caffeine from green tea can build up and hit harder.

In real life, that might mean feeling jittery, a racing heart, trouble sleeping, headache, or a higher blood pressure reading. A cup or two of green tea is unlikely to cause trouble for most folks, but concentrated extracts or lots of caffeine are more concerning, especially if you already have high blood pressure or heart issues. Please check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Brown NJ, Ryder D, Branch RA. A pharmacodynamic interaction between caffeine and phenylpropanolamine. Clin Pharmacol Ther 1991;50:363-71. PubMed
  2. Lake CR, Rosenberg DB, Gallant S, et al. Phenylpropanolamine increases plasma caffeine levels. Clin Pharmacol Ther 1990;47:675-85. PubMed
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

4 of 4

Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Green tea is unlikely to produce clinically significant changes in the levels and clinical effects of CYP3A4 substrates.
In vitro and in vivo research suggests that green tea can inhibit intestinal CYP3A and induce hepatic CYP3A4 enzymes. However, this effect is unlikely to be clinically significant, as green tea does not appear to affect CYP3A4 activity in humans.
Severity Minor Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Good news here. Anatuss combines a few cold and cough ingredients, and one of them (dextromethorphan, the cough suppressant) is partly handled by a liver enzyme called CYP3A4. In test tube studies, green tea showed mixed effects on this enzyme, blocking it in the gut while speeding it up in the liver. But when researchers looked at real people, green tea didn't meaningfully change how this enzyme works.

So in practice, drinking green tea is very unlikely to change how well your cough medicine works or cause extra drowsiness, dizziness, or jitteriness. This is based on lab data, not strong human evidence. If you're using concentrated green tea extract pills rather than the brewed drink, it's still smart to run that past your pharmacist, mostly because of liver concerns with high doses.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Donovan JL, Chavin KD, Devane CL, et al. Green tea (Camellia sinensis) extract does not alter cytochrome P450 3A4 or 2D6 activity in healthy volunteers. Drug Metab Dispos 2004;32:906-8. PubMed
  2. Nishikawa, M., Ariyoshi, N., Kotani, A., Ishii, I., Nakamura, H., Nakasa, H., Ida, M., Nakamura, H., Kimura, N., Kimura, M., Hasegawa, A., Kusu, F., Ohmori, S., Nakazawa, K., and Kitada, M. Effects of continuous ingestion of green tea or grape seed extrac
  3. Chow, H. H., Hakim, I. A., Vining, D. R., Crowell, J. A., Cordova, C. A., Chew, W. M., Xu, M. J., Hsu, C. H., Ranger-Moore, J., and Alberts, D. S. Effects of repeated green tea catechin administration on human cytochrome P450 activity. Cancer Epidemiol.B PubMed
  4. Engdal, S. and Nilsen, O. G. In vitro inhibition of CYP3A4 by herbal remedies frequently used by cancer patients. Phytother.Res. 2009;23(7):906-912.
  5. Schönthal AH. Adverse effects of concentrated green tea extracts. Mol Nutr Food Res. 2011 Jun;55(6):874-85. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • 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.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Green Tea Also Interacts With Other Medications

Green Tea has 13 major, 907 moderate, 373 minor known drug interactions in our database — the Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine one above is among them. If you take anything else, check it against the full list below.

Major 13 Moderate 907 Minor 373 No known interaction 1,537 (incl. Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine)
Taking anything else?

Check Another of Your Medications Against Green Tea

Covers the 2,830 medications we’ve checked against Green Tea. Pick one to open its full report.

From our Q&A

Questions About Green Tea or Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Green Tea or Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine

This page covers Green Tea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine page lists 261 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Ephedra (major) and Grapefruit (major).

By severity: 12 major · 206 moderate · 43 minor.

From our pharmacist’s overview on the Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine page

“Anatuss combines acetaminophen, dextromethorphan, guaifenesin, and phenylpropanolamine, and its supplement list is not one to skim, since 12 of the 261 ingredients on file carry a major rating. Two hazards top the pile.”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine interaction page

One more smart check

Taking Green Tea as Part of a Dietary Supplement Product? Check It for Interactions

We hold 9,084 real supplement products containing Green Tea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Green Tea. Your product may carry other ingredients that interact with Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine too, on top of Green Tea — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Green Tea and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Green Tea
Top 5%

#23 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine
Top 5%

#91 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Green Tea

What is Green Tea?

Green Tea
  • Antioxidant support
  • Weight loss
  • Heart health
  • Mental alertness
  • Cancer risk reduction

Green tea is a popular beverage rich in antioxidants called catechins, and drinking it in normal amounts is considered safe for most people. Concentrated green tea extracts are a different story—they may help modestly with weight or heart health for some, but high doses have been linked to rare liver problems. Talk to your pharmacist or doctor before taking green tea supplements, especially if you have liver concerns or are pregnant.

Read the full Green Tea monograph & all interactions
Keep checking

Other Drugs & Green Tea

Browse every other medication we’ve checked against Green Tea — both the ones with a known interaction and the ones without. Select any drug for the full detail.

13Major
907Moderate
373Minor
1,536No known interaction
13 Major 907 Moderate 373 Minor 1,536 No interaction
Major

13 interactions

Moderate

907 interactions

Showing 60 of 907 moderate interactions — see all 907 on the Green Tea page.

Minor

373 interactions

Showing 60 of 373 minor interactions — see all 373 on the Green Tea page.

No interaction 1,536 drugs checked — show the list

We also checked Green Tea against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,536 medications checked with no known interaction — see the full Green Tea list.

See the full Green Tea interactions page
See every supplement checked against Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

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

Keep exploring
Green Tea monograph › Uses, safety, and every drug interaction in one place Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine supplement interactions › Every supplement checked against Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine, ranked by severity Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Green Tea and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine Together: Common Questions

Can you take Green Tea with Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 4 interactions listed for Green Tea and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine?
Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine belongs to more than one drug category, and Green Tea interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Green Tea and Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Acetaminophen, Dextromethorphan, Guaifenesin, Phenylpropanolamine and Green Tea?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.