Coltsfoot

Medically reviewed by Prof. Giorgi Pkhakadze, MD, MPH, PhD — GMJ Editorial Board

What is Coltsfoot?

Coltsfoot (Tussilago farfara) is a perennial herb native to Europe and Asia that has been used in traditional medicine for centuries. The plant is easily recognizable by its distinctive hoof-shaped leaves and bright yellow flowers that appear before the leaves in early spring. Historically known as “coughwort” or “horsehoof,” coltsfoot has been primarily valued for its potential respiratory benefits.

The medicinal parts of coltsfoot include both the leaves and flowers, which contain various bioactive compounds including mucilage, flavonoids, and tannins. However, coltsfoot also contains pyrrolizidine alkaloids (PAs), which have raised significant safety concerns in recent decades. Due to these safety issues, coltsfoot supplements have been banned or restricted in several countries, including the United States, Canada, and parts of Europe.

Health benefits & uses

Respiratory conditions (Limited evidence): Traditional use of coltsfoot focused primarily on treating coughs, bronchitis, and other respiratory ailments. The mucilage content was believed to provide a soothing effect on irritated throat and bronchial tissues. However, modern clinical evidence supporting these uses is extremely limited, and safety concerns have largely overshadowed potential benefits.

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Anti-inflammatory effects (Limited evidence): Some preliminary laboratory studies have suggested that certain compounds in coltsfoot may possess anti-inflammatory properties. However, these findings have not been validated in human clinical trials, and the presence of toxic alkaloids makes therapeutic use inadvisable.

Wound healing (Limited evidence): Traditional topical applications of coltsfoot were sometimes used for minor skin irritations, though scientific evidence for these applications remains sparse and inconclusive.

How it works

The proposed mechanisms of action for coltsfoot’s traditional uses center around its mucilage content, which forms a protective gel-like coating that may theoretically soothe irritated mucous membranes. The flavonoids present in the plant may contribute to potential anti-inflammatory effects through inhibition of inflammatory mediators.

However, the pyrrolizidine alkaloids present in coltsfoot are metabolized in the liver to form reactive compounds that can cause cellular damage and DNA mutations. These toxic metabolites can accumulate in liver tissue and potentially lead to serious hepatotoxicity, making any therapeutic benefits questionable compared to the significant health risks.

Dosage

Due to safety concerns related to pyrrolizidine alkaloid content, no safe dosage recommendations can be provided for coltsfoot. The herb is banned for internal use in many jurisdictions, and health authorities strongly advise against its consumption. Even preparations claiming to be PA-free carry potential risks, as complete removal of these compounds is technically challenging to verify.

Anyone considering coltsfoot use should consult with a healthcare provider, though most medical professionals would recommend safer alternatives for respiratory or inflammatory conditions.

Food sources

Coltsfoot is not consumed as a food and has no nutritional value in the conventional sense. Historically, it was sometimes used as an herbal tea or smoking mixture, but these practices are now discouraged due to toxicity concerns. The plant grows wild in many temperate regions but should not be harvested for consumption.

Safety & side effects

Coltsfoot carries significant safety risks due to its pyrrolizidine alkaloid content. These compounds are hepatotoxic and potentially carcinogenic. Reported adverse effects include:

• Liver damage and hepatotoxicity
• Potential carcinogenic effects
• Veno-occlusive disease (blockage of liver blood vessels)
• Possible lung toxicity with prolonged exposure

Even short-term use may pose risks, particularly in individuals with existing liver conditions. The European Medicines Agency and FDA have issued warnings against coltsfoot use, and many countries have banned its sale as a dietary supplement.

Interactions

Coltsfoot may potentially interact with medications metabolized by the liver, as pyrrolizidine alkaloids can affect hepatic enzyme systems. Particular caution is warranted with:

• Hepatotoxic medications
• Blood thinning medications
• Medications requiring liver metabolism

Due to the significant safety profile, potential interactions are less relevant than the absolute contraindication for use in most circumstances.

Who should be cautious

Coltsfoot should be avoided by virtually everyone due to its toxicity profile. Particular caution is essential for:

• Pregnant and breastfeeding women
• Children and adolescents
• Individuals with liver disease
• People with compromised immune systems
• Anyone taking hepatotoxic medications

Frequently asked questions

Is coltsfoot safe if it’s labeled as pyrrolizidine alkaloid-free?

Even products claiming to be PA-free carry risks, as complete removal is difficult to verify and standardize. Most health authorities recommend avoiding coltsfoot entirely regardless of processing claims.

What are safer alternatives for respiratory support?

Safer herbal options for respiratory support may include marshmallow root, slippery elm, or licorice root, though any herbal treatment should be discussed with a healthcare provider.

Can coltsfoot be used topically?

Even topical use carries potential risks, as pyrrolizidine alkaloids can be absorbed through the skin. External use is generally not recommended.

Why was coltsfoot historically considered safe?

The toxic pyrrolizidine alkaloids in coltsfoot were not identified or understood until relatively recently. Traditional use predated modern toxicological analysis.

Is coltsfoot legal to purchase?

Coltsfoot supplements are banned or restricted in many countries including the US, Canada, and several European nations due to safety concerns.