Drug & supplement interaction

Squill + Psyllium , Senna (OTC drug)

Psyllium , Senna (OTC drug) brand name: Perdiem.

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

Squill has a moderate interaction with Psyllium , Senna (OTC drug). Squill contains cardiac glycosides. Concomitant use of squill and stimulant laxatives might increase the risk of cardiac glycoside toxicity due to potassium loss.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Squill and Psyllium , Senna (OTC drug)

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

Moderate

STIMULANT LAXATIVES

Why this applies to Psyllium , Senna (OTC drug)

Psyllium , Senna (OTC drug) falls under STIMULANT LAXATIVES — the group Squill interacts with.

Squill contains cardiac glycosides. Concomitant use of squill and stimulant laxatives might increase the risk of cardiac glycoside toxicity due to potassium loss.
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 concern with this combination. Perdiem contains senna, a stimulant laxative that gets your bowels moving. When laxatives like senna are used heavily or for a long time, your body can lose potassium through the stool. Low potassium is the key issue here, because squill works on the heart much like digoxin does.

When potassium runs low, those heart-acting compounds in squill can hit harder, which raises the risk of an irregular or dangerous heartbeat. So the laxative doesn't change squill directly, it just sets the stage by draining potassium. This is a theoretical worry based on how these substances work, not strong proof. Still, since squill can be genuinely toxic, please check with your pharmacist or doctor before pairing them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

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

Squill Also Interacts With Other Medications

Squill has 1 major, 154 moderate known drug interactions in our database — the Psyllium , Senna (OTC drug) one above is one of them. If you take anything else, check it against the full list below.

Major 1 Moderate 154 No known interaction 2,675 (incl. Psyllium , Senna (OTC drug))
Taking anything else?

Check Another of Your Medications Against Squill

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

Everything else you take

See Every Supplement That Interacts With Psyllium , Senna (OTC drug)

This page covers Squill only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Psyllium , Senna (OTC drug) page lists 46 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Jalap (major), Oleander (major), Alder Buckthorn (moderate) and Aloe (moderate).

By severity: 3 major · 34 moderate · 9 minor.

From our pharmacist’s overview on the Psyllium , Senna (OTC drug) page

“Perdiem pairs psyllium fiber with senna, a stimulant laxative, and that senna half is why this list of 46 interacting supplements calls for genuine care. Twenty-nine entries are stimulant laxative herbs themselves; layering them on senna compounds fluid and potassium loss, and the strongest of them, jalap, is rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Psyllium , Senna (OTC drug) interaction page

One more smart check

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

We hold 2 real supplement products containing Squill, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Squill. Your product may carry other ingredients that interact with Psyllium , Senna (OTC drug) too, on top of Squill — 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 Squill and Psyllium , Senna (OTC drug) 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 Squill
Top half

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

29 days ago today
Medication Psyllium , Senna (OTC drug)
Top 10%

#199 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 Squill

What is Squill?

Squill
  • Cough and chest congestion
  • Fluid retention (diuretic)
  • Heart conditions (traditional 'cardiac tonic')
  • Hair loss (topical use)
  • Rodenticide (red squill, non-medicinal)

Squill is a bulb plant that contains potent cardiac glycosides, which can affect the heart much like the drug digoxin. While it has a long history of use as a cough remedy and heart tonic, it can be dangerously toxic and there is little solid evidence for its modern use, so we do not recommend taking it without close medical supervision.

Read the full Squill monograph & all interactions
Keep checking

Other Drugs & Squill

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

1Major
154Moderate
0Minor
2,674No known interaction
1 Major 154 Moderate 2,674 No interaction
Major

1 interaction

Moderate

154 interactions

Showing 60 of 154 moderate interactions — see all 154 on the Squill page.

No interaction 2,674 drugs checked — show the list

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

Showing the 60 most looked-up of 2,674 medications checked with no known interaction — see the full Squill list.

See the full Squill interactions page
See every supplement checked against Psyllium , Senna (OTC drug), 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
Squill monograph › Uses, safety, and every drug interaction in one place Psyllium , Senna (OTC drug) supplement interactions › Every supplement checked against Psyllium , Senna (OTC drug), 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 Squill and Psyllium , Senna (OTC drug) Together: Common Questions

Can you take Squill with Psyllium , Senna (OTC drug)?
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 Squill and Psyllium , Senna (OTC drug) 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 Psyllium , Senna (OTC drug) and Squill?

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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.