Hound’s Tongue Plant Benefits: What the Evidence Actually Shows

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Hound’s tongue (Cynoglossum officinale) shows up in old European herbals as a wound plant: leaves mashed into poultices for burns, cracked hands, and sores that refused to close. If you have come here weighing the hounds tongue plant benefits against the risks, the honest summary fits in two sentences. The traditional skin uses are plausible but have never been tested in people. And the plant is loaded with pyrrolizidine alkaloids, natural compounds the liver turns into toxins.

That is not a scare line. It is the reason regulators treat this whole family of plants as a safety problem rather than a remedy. The U.S. Food and Drug Administration has advised companies to pull supplements containing any source of pyrrolizidine alkaloids from the market (FTC announcement of the FDA industry letter, 2001). Hound’s tongue is one of those sources.

So what can it actually do, what should you never do with it, and is there a version of the traditional use that still makes sense? Here is the whole picture.

What hound’s tongue is

Hound’s tongue is a biennial or short-lived perennial in the borage family, the same group that gives us comfrey, borage, and forget-me-nots. Native to Europe and Asia, it now grows across much of North America. It starts as a low rosette, then sends up a hairy stem one to four feet tall carrying clusters of small, dull reddish-purple flowers. The long, soft, rough leaves are what earned it the name. Each flower forms four barbed nutlets that grab onto fur, wool, socks, and dog ears (Washington State Noxious Weed Control Board).

Two practical things follow from that. First, in much of the western United States hound’s tongue is a listed noxious weed rather than a garden herb. In Washington it sits on both the noxious weed list and the state quarantine list, which makes it illegal to buy, sell, or distribute the plant or its seed there (Washington State Noxious Weed Control Board). Check your own state’s list before you plant, harvest, or move it.

Second, the same alkaloids that make it a livestock hazard are the reason it should not go in your tea.

The claimed hounds tongue plant benefits, graded honestly

Almost every benefit attached to this plant traces back to herbal tradition rather than to a trial. Here is where each claim actually stands.

Claimed benefit	What supports it	Evidence strength
Wound, burn, and ulcer healing (applied to skin)	Centuries of topical folk use, plus allantoin — a compound that encourages skin-repair cells to multiply and is used in ordinary pharmacy creams. No human trials of hound’s tongue itself.	Traditional plus mechanism only
Soothing dry, chapped, or irritated skin	Traditional use. Tannins and mucilage give a plausible calming, film-forming effect, which is also how several ordinary emollients work.	Traditional
Coughs, bronchitis, diarrhoea (taken by mouth)	Old herbals only. This is also the exact route that causes liver injury.	Insufficient, and not recommended
Pain relief and sedation	Nineteenth and twentieth-century herbals describe mildly sedative alkaloids. Those alkaloids are part of the toxicity problem, not a separate benefit.	Insufficient
Antioxidant or antimicrobial activity	Widely repeated online. The specific laboratory citations in circulation could not be located in any journal index, so treat this claim as unsupported until a real study surfaces.	Unverified

What that table adds up to: there are no controlled human trials of hound’s tongue for any condition. Anyone telling you it heals anything is describing tradition, not evidence.

What is actually inside the plant

The compound that gives hound’s tongue its reputation is allantoin. It is real, it is not exotic, and it appears in plenty of drugstore moisturisers and barrier creams. In its close relative comfrey, allantoin — alongside rosmarinic acid, tannins, and mucilage — is thought to be the basis of the plant’s soothing and wound-healing reputation (NIH LiverTox, 2022). That is a mechanistic explanation, not proof that a poultice works.

The compounds that matter far more are the pyrrolizidine alkaloids. Your liver metabolises them into reactive pyrrole molecules that bind to and damage the cells lining the liver’s small blood vessels (NIH LiverTox, 2022). The European Medicines Agency describes several of these alkaloids as both hepatotoxic and carcinogenic, and has issued formal recommendations covering both the oral and the skin-applied use of herbal products that contain them (EMA public statement on herbal medicines containing pyrrolizidine alkaloids, 2021).

How much is in the plant? A USDA-linked analysis of houndstongue harvested through a full growing season reported total alkaloid levels of roughly 1.5 to 2 percent of dry weight in young tissue, declining as the plant matured, with most of it present as the N-oxide form. [Unverified — the full paper could not be opened directly; see the verification report.]

For scale, that is a level of contamination regulators worry about in parts per billion, not percent.

Why hound’s tongue is never taken internally

Swallowed pyrrolizidine alkaloids cause hepatic sinusoidal obstruction syndrome, once called veno-occlusive disease. Small veins in the liver become blocked. In its acute form it can progress to liver failure within weeks; more often it creeps in with weight gain, fluid in the abdomen, weakness, and only mildly abnormal blood tests (NIH LiverTox, 2022).

The clearest human evidence comes from comfrey, hound’s tongue’s better-studied cousin, where published cases link comfrey teas and capsules to sinusoidal obstruction syndrome and severe liver injury. Infants appear to be especially vulnerable (NIH LiverTox, 2022). Oral comfrey is now banned or restricted in most countries. Hound’s tongue has never been through the same clinical scrutiny, but it belongs to the same family, carries the same class of alkaloids, and falls under the same regulatory advice.

There is no safe home dose. Decoctions, teas, tinctures, capsules, and root powders taken by mouth all fall under this. If you find a recipe telling you to drink a cup of hound’s tongue root decoction daily, that recipe predates the toxicology and should be ignored. The same logic applies to comfrey root, which is worth reading if you want the fuller version of this story in a plant that has actually been trialled.

What about putting it on the skin?

This is the honest grey area, and the sources genuinely disagree.

On one side: an in-vitro study using human skin tissue found that lycopsamine, one of the pyrrolizidine alkaloids in this plant family, is poorly absorbed through skin — which argues that topical risk has been overstated (NIH LiverTox, 2022). On the other: European regulators still thought cutaneous exposure warranted its own formal recommendations, and it is standard practice for licensed comfrey creams to be restricted to intact skin, adults, and short courses (EMA public statement, 2021). When the FTC required a warning label on topical comfrey products, that label read, in part: external use only, not to be applied to broken skin (FTC, 2001).

Both things can be true: skin is a decent barrier, and broken skin is not. The traditional uses for hound’s tongue — burns, ulcerations, cracked skin, slow-healing wounds — are precisely the situations where the barrier is already gone. That is the awkward part. The plant’s folk reputation points it at exactly the skin where the alkaloids would most easily get in.

Put plainly: there is no version of a homemade hound’s tongue poultice that is both traditional and safe. And unlike comfrey, there is no standardised, alkaloid-reduced hound’s tongue product on the market to fall back on.

Who should avoid hound’s tongue entirely

• Anyone considering swallowing it, in any form or amount.
• Pregnant women. Pyrrolizidine alkaloids can cross the placenta, and there is a published case of fatal liver injury in a newborn whose mother drank a pyrrolizidine-containing herbal tea through pregnancy.
• Breastfeeding women. These alkaloids can pass into milk, and infants are unusually susceptible to them.
• Infants and children.
• Anyone with liver disease, hepatitis, or a history of liver injury.
• Anyone with an open wound, burn, graze, ulcer, or active rash — the traditional indications are the wrong ones.
• Anyone drinking heavily or taking medication that leans on the liver. Enzyme-inducing drugs increase the toxicity of pyrrolizidine-containing substances, so the risk is not fixed — it depends on what else is going through your liver.

Side effects, interactions, and handling the plant

Handled in the field, hound’s tongue can cause contact dermatitis — the plant is listed as toxic to humans as well as livestock (Washington State Noxious Weed Control Board). Wear gloves if you are pulling it. The barbed nutlets are a nuisance on clothing and can lodge in a dog’s coat or eyelids.

On interactions, the honest answer is that hound’s tongue has not been studied for drug interactions in humans, so nothing specific can be listed. What is known is mechanistic: pyrrolizidine alkaloids are activated by liver enzymes, and enzyme inducers increase their toxicity (NIH LiverTox, 2022). Anything that stresses the liver — alcohol, paracetamol/acetaminophen, certain seizure and tuberculosis drugs — sits badly alongside a pyrrolizidine plant. Tell your doctor or pharmacist before combining anything.

If you keep livestock or horses, the risk is not theoretical. Animals generally avoid the living plant but will eat it dried in hay, and it damages the liver of cattle and horses in particular.

What to use instead

If what you actually want is help with a bruise, a sore joint, or dry cracked hands, there are better-supported options that do not carry a liver warning.

1. For bruises, sprains, and arthritic aches: standardised topical comfrey preparations have been through real randomised trials, and the safety rules for them are clear and published. See our full guide to comfrey root for the specifics.
2. For dry, cracked, or chapped skin: a plain fragrance-free emollient does the mechanical job — and if allantoin is the appeal, it is already an ingredient in many of them.
3. For minor cuts and grazes: clean water, gentle cleaning, and a simple dressing beat any poultice. Wound care is one of the few areas where the boring answer is genuinely the best one.
4. For soothing irritated skin generally: there are gentler traditional options with fewer safety strings attached. Our roundup of herbs for skin issues covers the alternatives.

Realistic expectations

Even setting the toxicity aside, nothing about this plant suggests a dramatic effect. Allantoin supports normal tissue repair; it does not accelerate it into something remarkable. Tannins tighten and dry; mucilage soothes. Those are modest, comfort-level actions, and they are available from a dozen safer plants and from ordinary pharmacy products.

Hound’s tongue is genuinely interesting botanically and historically. As a remedy in 2026, it is a plant whose risks are documented and whose benefits are not.

When to talk to a professional

See a doctor rather than reaching for a herbal remedy if you have:

• a wound that is deep, gaping, dirty, or will not stop bleeding
• spreading redness, warmth, swelling, pus, or fever around an injury
• a burn that blisters, covers a large area, or involves the face, hands, or genitals
• a skin ulcer that has not healed in a few weeks, especially with diabetes or poor circulation

Seek medical care urgently — and stop any pyrrolizidine-containing herb immediately — if you notice yellowing of the skin or eyes, dark urine, a swollen or painful abdomen, unexplained weight gain or fluid retention, or persistent nausea. Those are the presenting signs of sinusoidal obstruction syndrome (NIH LiverTox, 2022). Tell the clinician exactly what you took, how much, and for how long. That history matters, because the diagnosis is easy to miss.

Health disclaimer: This article is general education, not medical advice, and it is not a substitute for diagnosis or treatment by a qualified professional. Never take hound’s tongue by mouth in any form. If you are pregnant or breastfeeding, have liver disease or any other medical condition, take regular medication, or are considering a herbal remedy for a child, speak to a doctor or pharmacist first. If you think you have swallowed a pyrrolizidine-containing plant, contact a healthcare professional or your national poison centre.

Frequently Asked Questions

References

1. National Institute of Diabetes and Digestive and Kidney Diseases. “Comfrey.” LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Updated 24 May 2022. → View source
2. European Medicines Agency, Committee on Herbal Medicinal Products. “Use of herbal medicinal products containing toxic, unsaturated pyrrolizidine alkaloids (PAs).” Public statement EMA/HMPC/893108/2011 Rev. 1, adopted 2021. → View source
3. U.S. Federal Trade Commission. “FTC Announces a Second Case Focusing on Safety Risks of Comfrey Products Promoted via Internet.” 13 July 2001. Describes the FDA industry letter of 6 July 2001. → View source
4. Washington State Noxious Weed Control Board. “Houndstongue — Cynoglossum officinale.” Accessed July 2026. → View source
5. Pfister JA, Molyneux RJ, Baker DC. “Pyrrolizidine alkaloid content of houndstongue (Cynoglossum officinale L.).” Journal of Range Management 1992;45(3):254–256. → View source