Is Squill Tincture Safe? A Deep Dive into Its Uses and Risks

October 8, 2025 •

4 min read

Dating back to ancient Egypt, squill (Drimia maritima) has been used for everything from heart ailments to a rodenticide [1.5.1, 1.5.4]. Despite this long history, the answer to 'Is squill tincture safe?' is a definitive no for oral consumption due to its potent, toxic compounds [1.2.3, 1.2.8].

Quick Summary

Oral use of squill tincture is considered unsafe due to powerful cardiac glycosides that can cause severe gastrointestinal distress, life-threatening irregular heartbeats, and even death. It is not approved by the FDA for medicinal use.

Key Points

Unsafe for Oral Use: Taking squill tincture by mouth is unsafe due to toxic cardiac glycosides that can cause life-threatening heart problems and death [1.2.3].
Potent Cardiac Effects: Its active compounds strongly affect the heart, similar to the drug digoxin, but in unpredictable and dangerous concentrations [1.2.5, 1.2.3].
Not FDA Approved: Squill is not approved by the FDA as a safe or effective treatment for any health condition [1.2.5, 1.3.3].
High Risk of Side Effects: Common side effects include severe stomach irritation, vomiting, vision changes, confusion, and deadly irregular heartbeats [1.2.3, 1.2.8].
Numerous Drug Interactions: Squill interacts dangerously with diuretics, laxatives, corticosteroids, digoxin, and certain antibiotics, increasing toxicity risk [1.2.3].
Historical Use as Poison: Red squill's toxicity is so significant that it has historically been used as a rodenticide [1.2.4, 1.4.3].
Specific Contraindications: It is especially dangerous for pregnant women, people with heart disease, and those with electrolyte imbalances [1.2.3, 1.2.8].

Understanding Squill and Its Potent Nature

Squill, also known as sea onion, is a plant whose bulb has been used in traditional medicine for centuries, particularly for heart and respiratory conditions [1.5.1, 1.5.3]. A tincture is an alcoholic extract of plant material, which concentrates its active chemical constituents. In squill, these active compounds are primarily potent cardiac glycosides, such as scillaren A and proscillaridin A [1.2.5]. These substances have a powerful effect on the heart muscle, similar to the prescription drug digoxin [1.2.3]. While this action is the basis for its historical use in treating conditions like heart failure and edema ('dropsy'), it is also the source of its significant danger [1.5.2, 1.4.3]. The concentration and composition of these glycosides can vary depending on the plant's variety (red or white squill), harvest time, and preparation method, making any traditional preparation dangerously unpredictable [1.2.5, 1.6.6].

The Pharmacology of a Poison: How Squill Affects the Body

The cardiac glycosides in squill work by inhibiting the Na+/K+ ATPase pump in heart muscle cells [1.4.5, 1.5.8]. This leads to an increase in intracellular calcium, resulting in stronger heart contractions (a positive inotropic effect) [1.4.5, 1.5.8]. While this mechanism can be therapeutic in controlled, precise doses as seen with modern pharmaceuticals, the crude and variable nature of squill tincture makes it toxic. Overdosing is easy and can lead to a cascade of dangerous effects. Historically, red squill's toxicity was so well-known that it was a common rodenticide; its emetic properties would cause most animals to vomit the poison, but rats, which cannot vomit, would succumb to its cardiotoxic and convulsant effects [1.2.4, 1.4.3]. This same toxicity applies to humans when ingested.

Severe Health Risks and Side Effects

Oral consumption of squill tincture is declared unsafe by numerous health authorities [1.2.3, 1.2.8, 1.6.1]. The risks far outweigh any purported benefits, and there is no good scientific evidence to support most of its traditional uses [1.2.3].

The spectrum of adverse effects is wide and severe:

Gastrointestinal Distress: It is a powerful gastric irritant, causing nausea, vomiting, stomach pain, loss of appetite, and diarrhea [1.2.3, 1.6.2]. While vomiting can sometimes prevent a lethal dose from being absorbed, this is not a reliable safety mechanism [1.2.5].
Cardiotoxicity: This is the most life-threatening risk. Squill can cause serious and fatal cardiac arrhythmias (irregular heartbeats), including abnormally fast or slow heart rates and complete heart block [1.2.3, 1.4.5].
Neurological Symptoms: Headaches, confusion, depression, hallucinations, and vision changes have been reported [1.2.3]. In cases of severe poisoning, seizures can occur [1.2.3, 1.4.3].
Electrolyte Imbalance: Squill can worsen conditions of low potassium or high calcium, increasing the risk of cardiac side effects [1.2.8, 1.6.7].

Contraindications and Dangerous Interactions

Certain individuals should never take squill orally. It is strictly contraindicated for:

Pregnant or breastfeeding women: It is an abortifacient and can cause miscarriage [1.2.3, 1.2.9].
Individuals with heart disease: Using squill can lead to severe adverse effects in those with pre-existing heart conditions [1.2.3, 1.3.5].
People with stomach or bowel problems: Its irritant nature can exacerbate these conditions [1.2.3].
Those with low potassium levels: This significantly increases the risk of cardiac toxicity [1.2.8].

Squill also interacts dangerously with numerous medications:

Digoxin: Taking squill with digoxin can dangerously amplify its effects and side effects [1.2.3].
Diuretics (Water Pills) & Stimulant Laxatives: These can lower potassium levels, dramatically increasing the risk of squill's cardiotoxicity [1.2.3, 1.2.8].
Corticosteroids: These can also decrease potassium, leading to a similar increased risk [1.2.3].
Certain Antibiotics: Macrolide and tetracycline antibiotics may increase the body's absorption of squill, heightening its toxic effects [1.2.3].

Comparison Table: Squill Tincture vs. Digoxin


Feature	Squill Tincture	Digoxin (Pharmaceutical Drug)
Source	Crude extract of Drimia maritima plant bulb [1.2.5]	Purified compound, originally from Digitalis plant [1.5.2]
Standardization	Unstandardized; active compound levels are variable and unknown [1.2.5]	Highly purified and manufactured in precise, standardized doses [1.3.2]
Regulation	Not approved by the FDA for medicinal use; sold as an herbal supplement without safety or efficacy review [1.2.5, 1.3.3]	FDA-approved prescription medication for heart failure and atrial fibrillation [1.3.2]
Safety Profile	Considered unsafe for oral use; high risk of toxicity and fatal overdose [1.2.3, 1.2.8]	Has a narrow therapeutic window and requires medical supervision, but is safe when used as prescribed [1.2.3]
Primary Use	Traditionally for cough, edema, and heart issues; now largely obsolete and unsafe [1.5.4]	Medically supervised treatment of specific heart conditions [1.3.2]

Conclusion: A Historical Relic, Not a Modern Remedy

While squill has a long history in traditional herbalism, modern pharmacological understanding unequivocally shows that squill tincture is not safe for oral consumption. The active cardiac glycosides are potent toxins that can lead to severe poisoning and death [1.4.3, 1.4.5]. The lack of standardization, absence of regulatory oversight, and high potential for life-threatening side effects and drug interactions make it a dangerous substance to ingest [1.2.3, 1.2.5]. For conditions like heart failure or arrhythmias, FDA-approved, precisely dosed medications like digoxin are available and should be used under the guidance of a healthcare professional. The use of squill tincture as a folk remedy is a risk that should not be taken.

For authoritative information on poisons, contact a poison control center or a healthcare provider. An example of an authoritative source is the California Poison Control System. [1.4.6]

Frequently Asked Questions

Yes, squill may be available for purchase as an herbal supplement, which is not regulated by the FDA for safety or effectiveness before being marketed. Its availability does not mean it is safe to consume [1.2.5, 1.3.3].

The main active compounds are cardiac glycosides, which are potent toxins. These include bufadienolides like scillaren A, proscillaridin A, and scilliroside [1.2.5, 1.4.2].

While not a heart attack in the sense of a blockage, squill can cause fatal cardiac events like severe arrhythmias (irregular heartbeats), ventricular fibrillation, or complete heart block, leading to cardiac arrest and death [1.2.3, 1.4.3].

Oral use is considered unsafe. Some very limited research suggests a 2% topical solution applied to the scalp may be possibly safe for short-term use for alopecia areata, but more evidence is needed [1.2.3, 1.2.5].

Red squill contains compounds that are highly toxic and cause convulsions. It was effective against rats because they are unable to vomit, so they cannot expel the poison, unlike most other animals and humans who would likely vomit after ingestion [1.2.5, 1.4.3].

If you ingest squill, you should seek immediate medical attention or contact a poison control center. Symptoms can include vomiting, abdominal pain, confusion, and an irregular heartbeat [1.4.4].

No. While they have similar mechanisms of action on the heart, digoxin is a purified, FDA-approved prescription drug with a standardized dose. Squill is a crude, unpurified plant extract with unknown and variable concentrations of toxic compounds, making it unsafe [1.2.3, 1.3.2].