Squill (Drimia maritima) Supplement: Real Benefits, Risks, and Safe Use in 2025

Big promises sell. “Countless benefits” sounds great-until you’re the one swallowing a capsule. Squill, also known as Drimia maritima, has a long history in folk medicine and pharmacy, but it also contains cardiac glycosides-the same type of compounds doctors use under tight supervision for heart rhythm issues. That’s the gap most people don’t see: the line between herb and drug. If your goal is better breathing, better energy, or “heart support,” you need clear facts, not hype.

Here’s the short version: there are narrow, specific uses for squill in medicine, but as a general wellness supplement, the benefits are slim and the risks are real. You’ll leave this guide knowing what squill actually does, who should avoid it, what the law says in places like Australia, what to use instead, and what to do if you’ve already bought a bottle.

TL;DR

• Squill (Drimia maritima) contains cardiac glycosides (e.g., proscillaridin) with real pharmacology-and real toxicity. Not a casual wellness pill.
• Evidence for cough relief is old and limited; modern trials are sparse. For heart issues, glycosides are prescription drugs only.
• If you have heart disease, take digoxin, use diuretics, or have kidney issues-avoid squill unless your doctor explicitly prescribes a regulated product.
• Legal status varies. In Australia, cardiac glycosides like proscillaridin fall under prescription-only scheduling (Poisons Standard/SUSMP). Red squill extracts are used as rodenticides.
• Safer alternatives exist for cough/mucus: humidified air, honey (adults), guaifenesin, or thyme/ivy syrups with better safety profiles.

What Squill Is-and Isn’t: The Plant, the Claims, the Evidence

Squill is the bulb of Drimia maritima (formerly Urginea maritima), a Mediterranean plant with two main types: white squill and red squill. White squill found its way into old cough syrups and pharmacy texts; red squill became a rodenticide. The shared feature? Cardiac glycosides, notably proscillaridin A, which act on the heart. Useful in the right dose and context, dangerous if you guess wrong.

What marketers often promise: easier breathing, stronger heart, fat loss, anti-aging. What the science actually supports:

• Expectorant/cough: Historical use for loosening mucus. The German Commission E monographs (1990s) list squill bulb as an expectorant with caution due to cardiac glycosides. Modern, high-quality trials are scarce. A Cochrane review on over-the-counter cough medicines (Smith et al., updated through 2020) found mixed or insufficient evidence for many traditional expectorants; squill wasn’t backed by robust RCTs.
• Cardiac effects: Proscillaridin is a cardiac glycoside-pharmacologically similar to digoxin. These drugs can help in specific heart rhythm and heart failure situations under specialist care. Self-supplementing is risky. Major cardiology guidelines (e.g., ESC/ACC/AHA guidelines 2021-2023) treat cardiac glycosides as prescription-only agents with narrow roles and careful monitoring.
• Diuretic/edema: Mentioned historically, but modern clinical evidence is thin. If you need a diuretic, that’s a prescription conversation, not an herbal experiment.
• Antimicrobial/antioxidant: In vitro signals exist in lab studies, but petri dish activity doesn’t equal proven clinical benefit in humans.
• Weight loss, vitality, “countless benefits”: No credible human evidence. These are marketing claims, not outcomes shown in trials.

Regulatory and safety snapshots worth knowing:

• Australia (TGA/SUSMP): Cardiac glycosides such as proscillaridin are generally prescription-only (Schedule 4) substances under the Poisons Standard. That means DIY supplements containing meaningful amounts are not lawful consumer products. Check the latest SUSMP for specifics if you’re in Australia.
• United States: Proscillaridin is not an FDA-approved dietary supplement ingredient. Red squill extracts have a history in rodent control-hardly a wellness signal.
• Europe: Traditional herbal references (e.g., Commission E) note expectorant use but emphasize toxicity and dosing limits. Many countries restrict internal use outside pharmacy-grade products.

So where does this leave you? If your main goal is mucus relief during a cold, you have safer options that do not carry cardiac risk. If your goal is heart support, the right path is a cardiology plan-blood pressure control, statins if indicated, sodium management, exercise-not an unregulated glycoside.

Quick chemistry primer so the risk makes sense: cardiac glycosides inhibit Na+/K+ ATPase in heart muscle. That can increase intracellular calcium and boost contractility-handy in some medical settings. The tradeoff is a narrow therapeutic window. Too much, and you get arrhythmias, nausea, confusion, and vision changes. Even electrolyte shifts (like low potassium from a diuretic) can tip you into toxicity without changing the dose. This is why doctors order serum levels and check electrolytes with glycoside drugs.

If you came here eyeing a squill supplement, that’s the key reality check. You’re not just buying a plant; you’re buying a compound class that medicine handles with gloves.

The Safe-Use Playbook: Decisions, Risks, Interactions, and Better Options

Jobs-to-be-done after you click a headline like this are pretty clear: know if it works, know if it’s safe for you, figure out what to take instead if needed, and avoid getting burned by a sketchy product. Use this step-by-step flow to decide your next move.

1. Define your goal. Is it cough/mucus relief, “heart support,” or general wellness? The answer changes the plan.
2. If your goal is heart-related (palpitations, heart failure, blood pressure): do not use squill. Book a GP or cardiology visit. Cardiac glycosides are prescription territory with labs and monitoring. Self-dosing is not a shortcut; it’s a risk multiplier.
3. If your goal is cough/mucus relief: start with safe basics first for 3-5 days:
   • Humidified air and warm fluids.
   • Honey 1-2 teaspoons as needed (adults only; never in kids under 1 year).
   • Saline nasal irrigation for post-nasal drip.
   • Guaifenesin (expectoration aid) per label directions-evidence is mixed but safety is well characterized.
   • Consider thyme/ivy extracts-several European OTC syrups have supportive data and a safer profile than squill.
4. Check your risk factors before any herb with glycosides:
   • Heart disease, arrhythmia, heart block, or a pacemaker.
   • Kidney impairment.
   • Electrolyte issues, especially low potassium or magnesium.
   • Current use of digoxin or other glycoside, loop/thiazide diuretics, certain antiarrhythmics, macrolide antibiotics, or herbal stimulants.
   • Pregnancy, breastfeeding, or age under 18.
   If any of these fit, avoid squill unless a doctor prescribes and monitors a regulated product.
5. Legal and product check: Look up your country’s regulations. In Australia, consumer supplements with meaningful cardiac glycosides don’t belong on shelves. Be wary of vague labels like “proprietary squill blend” without standardization or glycoside content stated.
6. Already bought a bottle? If it lists Drimia/Urginea maritima with unspecified glycoside content, return it. If you choose to keep it against advice, do not stack with stimulants, diuretics, or heart meds, and stop immediately if you notice nausea, dizziness, slowed pulse, palpitations, yellow-green vision, or confusion. Seek medical care if symptoms appear.

Common side effects and red flags to know, adapted from pharmacology texts and clinical guidance:

• GI: Nausea, vomiting, abdominal pain, anorexia.
• Neuro/vision: Fatigue, confusion, headache, color vision changes (yellow/green halos).
• Cardiac: Bradycardia, AV block, premature beats, life-threatening arrhythmias.

High-risk interactions to avoid:

• Digoxin or other cardiac glycosides: additive toxicity.
• Loop/thiazide diuretics: hypokalemia raises glycoside toxicity risk.
• Macrolide antibiotics or certain antiarrhythmics: can alter rhythm risk or drug levels.
• Licorice (Glycyrrhiza), stimulant herbs, or high-dose caffeine: electrolyte shifts or arrhythmia risk.
• St. John’s wort: enzyme induction may alter levels unpredictably.

Decision rules of thumb:

• If you need a cough aid and have any heart history, skip squill and choose non-glycoside options.
• If a label hides standardization numbers, pass.
• If your symptoms include chest pain, breathlessness at rest, or fainting, see a doctor-not a supplement aisle.

Comparing squill to practical alternatives:

A quick buyer’s checklist if you’re still tempted by a fancy listing online:

• Does the product clearly state glycoside content and standardization? If not, skip.
• Is the seller dodging the words “Drimia maritima” or “cardiac glycoside”? Red flag.
• Any claim to “cure heart failure” or “replace prescriptions”? Walk away.
• Third-party testing (e.g., ISO-accredited lab) mentioned? If no, pass.
• Country of sale aligns with your local law (e.g., TGA in Australia)? If not, don’t import guesswork.

Safer, evidence-aligned swaps for common goals:

• Thick mucus: Fluids, humidifier, guaifenesin, thyme/ivy, brief trial of saline nebulization if advised.
• “Heart support”: Doctor-guided plan-blood pressure under control, statins if indicated, sleep, Mediterranean-style eating, regular walking/resistance training. Supplements with reasonable evidence for specific niches: omega-3s for very high triglycerides; magnesium for palpitations in some cases (only if levels are low and your doctor agrees).
• Energy/fatigue: Sleep, iron/B12 if deficient, hydration, smart training volume. Herbs promising “stim” often trade short-term buzz for long-term crash.

FAQs, Scenarios, and Next Steps

Is squill legal to buy as a supplement in Australia?
In Australia, substances with cardiac glycoside activity like proscillaridin are generally prescription-only under the Poisons Standard (SUSMP). Products marketed as casual supplements that contain meaningful amounts would not be compliant. If you see a grey-market listing, treat it as suspect.

Is squill safe at “microdose” levels?
“Microdose” is a marketing word, not a safety guarantee. Cardiac glycosides have steep dose-response curves and individual variability. Electrolyte shifts, dehydration, or drug interactions can turn a “small” dose into a problem. Without medical oversight and standardization, you’re guessing.

Can I use squill if I’m already on digoxin?
No. Additive effects raise toxicity risk. Any cardiac glycoside combo is a hard stop unless a cardiologist directs it. If you accidentally combined them, call your doctor or seek urgent care if symptoms arise.

What about red squill? It’s natural, right?
Red squill extracts have a history as rodenticides. That should tell you what you need to know about safety for humans and pets.

Does squill help chronic bronchitis?
Older European texts list squill as an expectorant in chronic bronchitis. Modern evidence is limited, and safer options exist. If you have chronic bronchitis/COPD, work with your GP on inhaled therapies and pulmonary rehab. Don’t self-medicate with glycosides.

Can athletes use squill for performance?
Bad idea. Cardiac glycosides can provoke dangerous arrhythmias when training hard, especially in heat or with dehydration. There’s no legitimate performance upside that outweighs those risks.

Is squill okay during pregnancy or breastfeeding?
No. Avoid. Safety data are lacking and the mechanism raises concern. Talk to your obstetrician for any medication or supplement.

What if my cough lasts more than 3 weeks?
See a clinician. Post-viral cough, asthma, reflux, or pertussis may be at play. That’s a diagnostic problem, not a supplement problem.

What primary sources back the cautions here?
Key references include the German Commission E monographs (1990s) for historical indications and warnings; Cochrane reviews on OTC cough medicines (Smith et al., updated through 2020) showing limited evidence for many expectorants; cardiology guidelines from ESC/ACC/AHA (2021-2023) clarifying the narrow, monitored role of cardiac glycosides; and the Australian Poisons Standard (SUSMP, latest editions through 2024) scheduling cardiac glycosides as prescription-only. Toxicology and pharmacology texts describe classic glycoside toxicity signs (GI upset, vision changes, arrhythmias).

Next steps by scenario:

• You want cough relief fast: Try honey (adults), humidifier, fluids, and guaifenesin for 3-5 days. Add thyme/ivy syrup if you like herbal options. If fever persists beyond 3 days, shortness of breath worsens, or cough lasts over 3 weeks, book an appointment.
• You have a heart condition or take heart meds: Skip squill. Ask your doctor about fit-for-purpose treatments and whether your current plan needs a tune-up. Bring a full list of meds and supplements to avoid interactions.
• You bought squill already: Read the label. If glycosides aren’t standardized and safety info is vague, return it. If you’ve taken it and feel dizzy, nauseous, or notice slow/irregular pulse or yellow-green vision, seek care.
• You’re in Australia and saw an overseas listing: Check TGA’s public resources or ask a pharmacist before importing anything with cardiac activity. Border seizures and safety risks aren’t worth the gamble.
• You prefer “natural” but want safety: Pick herbs with better safety windows and clinical backing for your goal-thyme/ivy for cough, ginger for nausea, psyllium for digestion. Natural isn’t a shield; dose and mechanism matter.

Quick troubleshooting tips:

• Thick mucus won’t budge: Increase water intake, use a warm shower or steam inhalation, check room humidity (40-50%), and consider a short course of guaifenesin. If you wheeze or feel chest tightness, get checked for asthma.
• Frequent palpitations: Log episodes (time, triggers, caffeine intake), cut back on stimulants, and see a GP for ECG and labs (thyroid, electrolytes, magnesium). Supplements aren’t the first move.
• On diuretics with cramps: Ask your doctor about checking potassium and magnesium. Do not add a glycoside herb; you’re in the highest-risk group for toxicity.

Bottom line for smart shoppers: squill is a pharmacy-class plant, not a daily wellness booster. If you need an expectorant, safer tools are a short reach away. If you need heart help, that starts with a doctor, not a glossy bottle. Save your money, protect your rhythm, and pick the option that matches the evidence-and your life.

Note: This guide is general information for adults and isn’t medical advice. If you have symptoms or conditions mentioned here, talk with your doctor or pharmacist.