Drug & supplement interaction

Job's Tears + Guaifenesin

Guaifenesin brand names: Robitussin, Humibid LA, Amibid LA, Numobid, Muco-Fen 800, and others.

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

Job's Tears has a moderate interaction with Guaifenesin. Animal research suggests that Job's tears might enhance absorption of dextromethorphan in the small intestine.

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

Job's Tears and Guaifenesin

Here is the interaction we found between these two, with the evidence behind it.

Moderate

DEXTROMETHORPHAN (Robitussin DM, others)

Animal research suggests that Job's tears might enhance absorption of dextromethorphan in the small intestine. Single dose oral administration of Job's tears bran ethanolic extract along with oral administration of a five-drug cocktail containing dextromethorphan increases dextromethorphan area under the plasma concentration-time curve (AUC) without altering major cytochrome P450 activities in the liver. This effect has not been reported in humans.
Severity Moderate Likelihood Possible Evidence D

Interaction 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.

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

Here's the honest picture for guaifenesin (Robitussin, Mucinex, and similar): the interaction we have on file actually involves dextromethorphan, a cough medicine often paired with guaifenesin in combination products. In animal studies, an extract of Job's Tears bran appeared to boost how much dextromethorphan got absorbed from the gut. That's why guaifenesin gets lumped into the same category.

For guaifenesin itself, this is really a non-issue. Guaifenesin simply loosens mucus so you can cough it up, and it isn't activated or heavily processed by the liver enzymes involved here. Even if Job's Tears nudged absorption a little, guaifenesin has a very wide safety margin and mild effects at most (occasional nausea or upset stomach). The evidence is also weak, based on lab and animal work, not people. Food amounts of Job's Tears are nothing to worry about. If you take a concentrated supplement and have questions, check with your pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Yao HT, Lin JH, Liu YT, Li ML, Chiang W. Food-Drug Interaction between the Adlay Bran Oil and Drugs in Rats. Nutrients 2019;11(10):2473. 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

Job's Tears Also Interacts With Other Medications

Job's Tears has 127 moderate known drug interactions in our database — the Guaifenesin one above is one of them. If you take anything else, check it against the full list below.

Moderate 127 No known interaction 2,703 (incl. Guaifenesin)
Taking anything else?

Check Another of Your Medications Against Job's Tears

Covers the 2,830 medications we’ve checked against Job's Tears. Pick one to open its full report.

From our Q&A

Questions About Job's Tears or Guaifenesin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Job's Tears or Guaifenesin, 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 Guaifenesin

This page covers Job's Tears only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Guaifenesin page lists 26 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Berberine (moderate), Bitter Orange (moderate) and Coffee Charcoal (moderate).

By severity: 2 major · 15 moderate · 9 minor.

From our pharmacist’s overview on the Guaifenesin page

“Guaifenesin (Robitussin, Humibid LA) loosens chest mucus, and by itself it is a mild medicine, but two of the 26 supplements on this list rate major, so those two deserve your attention first. Activated charcoal can bind the drug in your gut and blunt what it does, and grapefruit raises blood levels of dextromethorphan, the cough suppr…”

Reviewed by 2 · Jul 18, 2026

Open the Guaifenesin interaction page

One more smart check

Taking Job's Tears as Part of a Dietary Supplement Product? Check It for Interactions

We hold 111 real supplement products containing Job's Tears, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Job's Tears. Your product may carry other ingredients that interact with Guaifenesin too, on top of Job's Tears — 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 Job's Tears and Guaifenesin 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 Job's Tears
Top half

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

29 days ago today
Medication Guaifenesin
Steady interest

#2,006 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 Job's Tears

What is Job's Tears?

  • Digestive support
  • Skin health and smoothness
  • Mild swelling or water retention
  • General nourishing food/tonic
  • Joint discomfort (traditional use)

Job's Tears is a grain-like seed long used as a food and in traditional medicine, especially in East Asia. While it is generally safe as a food and is being studied for possible effects on metabolism, inflammation, and immunity, strong human evidence for its health claims is limited. Talk with your pharmacist or doctor before using concentrated supplements, especially during pregnancy.

Read the full Job's Tears monograph & all interactions
Medication

About Guaifenesin

What Is Guaifenesin Used For?

Brand names: Robitussin, Humibid LA, Amibid LA, Numobid, Muco-Fen 800, Bidex, Organidin, X-pect, Mucinex

Guaifenesin helps loosen phlegm (mucus) and thin bronchial secretions — the thick fluid in your airways — so your body can clear them out more easily and make coughs more productive.

It is available in multiple forms and brands, including oral solutions, regular tablets, and extended-release tablets, all for this same purpose of relieving chest congestion.

See full Guaifenesin drug information
Keep checking

Other Drugs & Job's Tears

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

0Major
127Moderate
0Minor
2,702No known interaction
127 Moderate 2,702 No interaction
Moderate

127 interactions

Showing 60 of 127 moderate interactions — see all 127 on the Job's Tears page.

No interaction 2,702 drugs checked — show the list

We also checked Job's Tears against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,702 medications checked with no known interaction — see the full Job's Tears list.

See the full Job's Tears interactions page
See every supplement checked against Guaifenesin, 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
Job's Tears monograph › Uses, safety, and every drug interaction in one place Guaifenesin supplement interactions › Every supplement checked against Guaifenesin, ranked by severity Guaifenesin drug information › The full plain-English guide to this medication 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 Job's Tears and Guaifenesin Together: Common Questions

Can you take Job's Tears with Guaifenesin?
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.
How serious is the Job's Tears and Guaifenesin 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 Guaifenesin and Job's Tears?

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.