Drug & supplement interaction

Ilex Guayusa + Cefaclor

Cefaclor brand names: Ceclor CD, Ceclor.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Oct 4, 2026
The bottom line No known interaction

We found no known interaction between Ilex Guayusa and Cefaclor in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Cefaclor states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Ilex Guayusa and Cefaclor

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Cefaclor and Ilex Guayusa in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Ilex Guayusa safety at a glance

Ilex Guayusa overall Use caution Generally well tolerated in tea amounts, but it contains caffeine that can cause stimulant side effects.
Pregnancy Use caution Limit or avoid because of its caffeine content and a lack of safety studies in pregnancy.
Breastfeeding Use caution Caffeine passes into breast milk, so limit intake or avoid until more is known.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Cefaclor and Ilex Guayusa? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Cefaclor

Interactions in our licensed database are recorded against drug classes, not just single drug names. Cefaclor is filed under 6 classifications — including organic anion transporter 3 (oat3) substrates, organic anion transporter 1 (oat1) substrates, antibiotic drugs. Ilex Guayusa has documented interactions with 37 drug classes — the most serious being ephedrine (major), adenosine (adenocard) (moderate) and anticoagulant/antiplatelet drugs (moderate) — and none of Cefaclor’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Ilex Guayusa Does Interact With Other Medications

Ilex Guayusa has 8 major, 470 moderate, 127 minor known drug interactions in our database — Cefaclor isn’t one of them. If you take anything else, check it against the full list below.

Major 8 Moderate 470 Minor 127 No known interaction 2,225 (incl. Cefaclor)
Taking anything else?

Check Another of Your Medications Against Ilex Guayusa

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

What to actually watch for

No Interaction Found — But Data Suggests Ilex Guayusa and Cefaclor May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. One of them is worth acting on rather than waiting out — marked below.

  • Confusion Worth acting on Additional detail

    Ilex Guayusa

    “Chronic use of caffeine, especially in large amounts, may produce tolerance, habituation, and psychological dependence. There is some concern that stopping regular use of caffeine may cause withdrawal symptoms such as headache, tiredness and fatigue, decreased energy, alertness, and attentiveness, drowsiness, decreased contentedness, depressed mood, difficulty concentrating, irritability, and lack of clear-headedness…”

    Ilex Guayusa · Natural Medicines adverse-effect record, reported in anxiety.

    5 sources cited
    1. 3719. Boozer CN, Nasser JA, Heymsfield SB, et al. An herbal supplement containing Ma Huang-Guarana for weight loss: a randomized, double-blind trial. Int J Obes Relat Metab Disord 2001;25:316-24. PubMed
    2. 13738. Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology (Berl) 2004;176:1-29. PubMed
    3. 2723. Dews PB, Curtis GL, Hanford KJ, O'Brien CP. The frequency of caffeine withdrawal in a population-based survey and in a controlled, blinded pilot experiment. J Clin Pharmacol 1999;39:1221-32. PubMed
    4. 11839. Dews PB, O'Brien CP, Bergman J. Caffeine: behavioral effects of withdrawal and related issues. Food Chem Toxicol 2002;40:1257-61. PubMed
    5. 13736. Anderson BJ, Gunn TR, Holford NH, Johnson R. Caffeine overdose in a premature infant: clinical course and pharmacokinetics. Anaesth Intensive Care 1999;27:307-11. PubMed

    Cefaclor

    Listed in the ADVERSE REACTIONS section of the FDA label for Cefaclor. Read the label on DailyMed ›

  • Drowsiness / Tiredness / Headache Additional detail

    Ilex Guayusa

    Recorded for Ilex Guayusa in the same Natural Medicines adverse-effect record shown under Confusion above.

    Cefaclor

    Listed in the ADVERSE REACTIONS section of the FDA label for Cefaclor. Read the label on DailyMed ›

  • Anxiety or restlessness Additional detail

    Ilex Guayusa

    “Orally, jitteriness increased in females, but not males, taking a single dose of guayusa extract in a clinical trial. The level of jitteriness reported was greater in those taking 1200 mg than those taking 600 mg. In one clinical trial, a study participant reported tremors after taking a single 650 mg dose of guayusa extract.”

    Ilex Guayusa · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    2 sources cited
    1. 115148. Helwig NJ, Schwager LE, Berry AC, et al. Acute, dose-response effects of guayusa leaf extract on mood, cognitive and motor-cognitive performance, and blood pressure, heart rate, and ventricular repolarization. J Int Soc Sports Nutr 2024;21(1):2379424. PubMed
    2. 113625. La Monica MB, Raub B, Ziegenfuss EJ, et al. Acute effects of naturally occurring guayusa tea and Nordic lion's mane extracts on cognitive performance. Nutrients 2023;15(24):5018. PubMed

    Cefaclor

    Listed in the ADVERSE REACTIONS section of the FDA label for Cefaclor. Read the label on DailyMed ›

  • Swelling Additional detail

    Ilex Guayusa

    “Some evidence shows that caffeine, a constituent of Ilex guayusa, is associated with fibrocystic breast disease, breast cancer, and endometriosis in females; however, this is controversial since findings are conflicting. Restricting caffeine in females with fibrocystic breast conditions doesn't seem to affect breast nodularity, swelling, or pain.”

    Ilex Guayusa · Natural Medicines adverse-effect record, reported in breast cancer.

    5 sources cited
    1. 8043. Ferrini RL, Barrett-Connor E. Caffeine intake and endogenous sex steroid levels in postmenopausal women. The Rancho Bernardo Study. Am J Epidemiol 1996:144:642-4. PubMed
    2. 8996. Horner NK, Lampe JW. Potential mechanisms of diet therapy for fibrocystic breast conditions show inadequate evidence of effectiveness. J Am Diet Assoc 2000;100:1368-80. PubMed
    3. 108806. Zheng KH, Zhu K, Wactawski-Wende J, et al. Caffeine intake from coffee and tea and invasive breast cancer incidence among postmenopausal women in the Women's Health Initiative. Int J Cancer 2021;149(12):2032-2044. PubMed
    4. 108807. Wang S, Li X, Yang Y, et al. Does coffee, tea and caffeine consumption reduce the risk of incident breast cancer? A systematic review and network meta-analysis. Public Health Nutr 2021;24(18):6377-6389. PubMed
    5. 91023. Beaudoin MS, Allen B, Mazzetti G, Sullivan PJ, Graham TE. Caffeine ingestion impairs insulin sensitivity in a dose-dependent manner in both men and women. Appl Physiol Nutr Metab. 2013;38(2):140-7. doi: 10.1139/apnm-2012-0201. Epub 2012 9. PubMed

    Cefaclor

    Listed in the ADVERSE REACTIONS section of the FDA label for Cefaclor. Read the label on DailyMed ›

Reported for Ilex Guayusa but not commonly for Cefaclor: trouble concentrating, dependence or withdrawal symptoms, raised blood pressure and low mood.

Effects for Cefaclor come from the ADVERSE REACTIONS section of its FDA label; effects for Ilex Guayusa come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Cefaclor Products Have a Food Rule — Ilex Guayusa Should Not Break It

At least one FDA label for a product containing Cefaclor says to take it with food. If you take Ilex Guayusa on an empty stomach out of habit, keep them separate — and take Cefaclor with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Cefaclor products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

DOSAGE AND ADMINISTRATION The absorption of cefaclor extended-release tablets is enhanced when it is administered with food.

From the Dosage and Administration section of the FDA label we read for Cefaclor — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Cefaclor

This page covers Ilex Guayusa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cefaclor page lists 60 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Siberian Cocklebur (major), African Wild Potato (moderate) and Aristolochia (moderate).

By severity: 3 major · 46 moderate · 11 minor.

From our pharmacist’s overview on the Cefaclor page

“The entries worth understanding before any others on this cefaclor (Ceclor) page are the kidney risks and charcoal. Cefaclor is a cephalosporin antibiotic, typically a short course for ear, sinus, throat, or skin infections, and two herbs here, Siberian cocklebur and asarabacca, can damage the kidneys on their own, so pairing either wi…”

Reviewed by 2 · Jul 18, 2026

Open the Cefaclor interaction page

How much people look this up

Where Ilex Guayusa and Cefaclor 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 Ilex Guayusa
Steady interest

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

29 days ago today
Medication Cefaclor
Top 10%

#241 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Ilex Guayusa reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Ilex Guayusa and Cefaclor records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Ilex Guayusa

What is Ilex Guayusa?

  • Energy and alertness
  • Mental focus
  • Antioxidant support
  • Appetite control
  • Athletic and physical performance

Ilex guayusa is a caffeine-containing holly leaf from the Amazon, traditionally brewed as a tea for energy and alertness, much like yerba mate or green tea. There is limited human research confirming specific health benefits, and its main reliable effect comes from its caffeine content. Because it is a stimulant, use it cautiously and check with your pharmacist or doctor if you have heart concerns or are pregnant.

Ilex guayusa · Aquifoliaceae · Leaves · Tea, brewed infusion, capsules, powdered extract, energy drinks

An interaction check asks whether these two react with each other — it does not ask whether Ilex Guayusa is a good idea for someone in your situation. Here is what our Ilex Guayusa record says about it on its own.

Ilex Guayusa: dosing

There is no official standardized dose for guayusa. It is most commonly taken as a brewed tea, and the amount of caffeine you get can vary widely depending on how much leaf you use and how long you steep it.If you use a packaged product, follow the directions on the label and do not exceed the recommended serving. Keep your total daily caffeine from all sources in mind.

From our Ilex Guayusa monograph — the full record covers uses, side effects and every documented interaction.

Read the full Ilex Guayusa monograph & all interactions
Medication

About Cefaclor

What Is Cefaclor Used For?

Brand names: Ceclor CD, Ceclor

Cefaclor treats a range of bacterial infections. The capsule and oral suspension forms are used for ear infections (otitis media), lower respiratory tract infections including pneumonia, strep throat and tonsillitis, urinary tract infections (including kidney infections and bladder infections), and skin and skin structure infections.

The extended-release tablet form of Cefaclor is approved for a narrower set of uses: acute bacterial flare-ups of chronic bronchitis, strep throat and tonsillitis, and uncomplicated skin infections. Not all infections approved for the capsule or suspension are approved for the extended-release tablet — your prescriber will choose the right form for your infection.

Most-Reported Side Effects for Cefaclor

From FAERS, the FDA’s public side-effect reporting system (1,535 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Drug hypersensitivity 252 reports
Nausea 159 reports
Vomiting 159 reports
Fatigue 137 reports
Fever 121 reports
See full Cefaclor drug information
Keep checking

Other Drugs & Ilex Guayusa

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

8Major
470Moderate
127Minor
2,224No known interaction
8 Major 470 Moderate 127 Minor 2,224 No interaction
Major

8 interactions

Moderate

470 interactions

Showing 60 of 470 moderate interactions — see all 470 on the Ilex Guayusa page.

Minor

127 interactions

Showing 60 of 127 minor interactions — see all 127 on the Ilex Guayusa page.

No interaction 2,224 drugs checked — show the list

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

Showing the 60 most looked-up of 2,224 medications checked with no known interaction — see the full Ilex Guayusa list.

See the full Ilex Guayusa interactions page
See every supplement checked against Cefaclor, ranked by severity
Evidence & sources

Ilex Guayusa References

The 90 references that drive our Ilex Guayusa monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Harder S, Fuhr U, Staib AH, Wolff T. Ciprofloxacin-caffeine: a drug interaction established using in vivo and in vitro investigations. Am J Med 1989;87:89S-91S. PubMed
  3. Carbo M, Segura J, De la Torre R, et al. Effect of quinolones on caffeine disposition. Clin Pharmacol Ther 1989;45:234-40. PubMed
  4. Healy DP, Polk RE, Kanawati L, et al. Interaction between oral ciprofloxacin and caffeine in normal volunteers. Antimicrob Agents Chemother 1989;33:474-8. PubMed
  5. Mester R, Toren P, Mizrachi I, et al. Caffeine withdrawal increases lithium blood levels. Biol Psychiatry 1995;37:348-50. PubMed
  6. Jefferson JW. Lithium tremor and caffeine intake: two cases of drinking less and shaking more. J Clin Psychiatry 1988;49:72-3.
  7. Joeres R, Klinker H, Heusler H, et al. Influence of mexiletine on caffeine elimination. Pharmacol Ther 1987;33:163-9. PubMed
  8. Vahedi K, Domingo V, Amarenco P, Bousser MG. Ischemic stroke in a sportsman who consumed MaHuang extract and creatine monohydrate for bodybuilding. J Neurol Neurosurg Psychiatr 2000;68:112-3.
  9. Wakabayashi K, Kono S, Shinchi K, et al. Habitual coffee consumption and blood pressure: A study of self-defense officials in Japan. Eur J Epidemiol 1998;14:669-73. PubMed
  10. Hodgson JM, Puddey IB, Burke V, et al. Effects on blood pressure of drinking green and black tea. J Hypertens 1999;17:457-63. PubMed
  11. Rapuri PB, Gallagher JC, Kinyamu HK, Ryschon KL. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes. Am J Clin Nutr 2001;74:694-700. PubMed
  12. Pollock BG, Wylie M, Stack JA, et al. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol 1999;39:936-40. PubMed
  13. Nurminen ML, Niittynen L, Korpela R, Vapaatalo H. Coffee, caffeine and blood pressure: a critical review. Eur J Clin Nutr 1999;53:831-9. PubMed
  14. Dews PB, Curtis GL, Hanford KJ, O'Brien CP. The frequency of caffeine withdrawal in a population-based survey and in a controlled, blinded pilot experiment. J Clin Pharmacol 1999;39:1221-32. PubMed
  15. Boozer CN, Nasser JA, Heymsfield SB, et al. An herbal supplement containing Ma Huang-Guarana for weight loss: a randomized, double-blind trial. Int J Obes Relat Metab Disord 2001;25:316-24. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Ilex Guayusa and Cefaclor Together: Common Questions

Is it safe to take Ilex Guayusa with Cefaclor?
We do not list a known interaction between Ilex Guayusa and Cefaclor. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Ilex Guayusa and Cefaclor have any of the same side effects?
Yes — our sources link each of them separately to 6 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Ilex Guayusa and Cefaclor at the same time of day?
At least one FDA label for a product containing Cefaclor says to take it with food. If you take Ilex Guayusa on an empty stomach out of habit, keep them separate and take Cefaclor with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Cefaclor products can differ — so check the directions on your own box. This is about absorption, not an interaction.
How was the Ilex Guayusa and Cefaclor combination checked?
Interactions in our licensed database are recorded against drug classes. Cefaclor is filed under 6 classifications, and Ilex Guayusa has documented interactions with 37 drug classes — none of Cefaclor's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Ilex Guayusa interact with any other medications?
Yes. Ilex Guayusa has 605 documented drug interactions in our database — Cefaclor is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Cefaclor interact with any supplements?
Yes. Cefaclor has documented interactions with 60 supplements in our database — Ilex Guayusa is not one of them. The Cefaclor interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Ilex Guayusa monograph Uses, safety profile, and every drug interaction in one place Cefaclor drug information The full plain-English guide to this medication Cefaclor supplement interactions Every supplement checked against Cefaclor, 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 References The 90 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Cefaclor and Ilex Guayusa?

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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.