Are There Any Poisonous Mints?

December 19, 2025 •

3 min read

While many beloved culinary mints are entirely safe to consume, certain species within the larger mint family are notably poisonous. Knowing how to distinguish common, edible mints from their harmful counterparts is crucial for any gardener or forager asking, "Are there any poisonous mints?".

Quick Summary

Several species within the mint family are toxic, most notably pennyroyal and perilla mint. Accurate identification is essential to avoid potential harm from these plants or look-alikes.

Key Points

Pennyroyal is a Poisonous Mint: European Pennyroyal (Mentha pulegium) is toxic, and its concentrated oil is extremely dangerous to humans and pets.
Perilla Mint Threatens Livestock: Perilla mint is highly toxic to livestock like cattle and horses, though less so to humans in smaller amounts.
Look-alikes Exist: Poisonous plants such as water hemlock and stinging nettle can be mistaken for mint, so relying on a single trait like scent is unsafe.
Square Stems Indicate the Mint Family: While not all mints are safe, a square stem is a reliable sign that a plant belongs to the Lamiaceae family.
Always Verify Identification: Never consume a wild plant unless you are 100% certain of its identity and confirm it's not a toxic species.
Even Edible Mints Can Be Harmful in Excess: Large quantities of even safe mints can cause digestive upset in humans and pets.

The widespread popularity of herbs like spearmint and peppermint often leads to the assumption that all mint-like plants are safe for consumption. However, within the vast Lamiaceae family, there exist species that are far from harmless. The key to safe foraging and gardening is to recognize the dangerous exceptions that can be mistaken for their benign cousins.

Truly Poisonous Mints

European Pennyroyal (Mentha pulegium)

European Pennyroyal is arguably the most infamous of the toxic mints. It contains high levels of pulegone, a compound that can cause severe liver damage and even death if ingested in concentrated amounts. Historically used as an abortifacient, its concentrated oil is extremely dangerous and should never be consumed. While a few leaves may not be acutely toxic to a healthy adult, the plant should still be avoided entirely due to its risk and similarity to edible mints. European Pennyroyal is a creeping groundcover with smaller leaves and distinctly different flowers than common peppermint.

Perilla Mint (Perilla frutescens)

Also known as rattlesnake weed or purple mint, Perilla mint is primarily toxic to livestock, including cattle and horses. It contains perilla ketone, which can cause severe respiratory issues and death in grazing animals. While less toxic to humans, large quantities can still be harmful. The risk of accidental ingestion is highest when the plant is baled with hay. Perilla mint features green to purplish leaves with toothed margins and a distinct odor when crushed.

Dangerous Mint Look-alikes

American Pennyroyal (Hedeoma pulegioides)

Though not a true Mentha species, American Pennyroyal is in the mint family and contains the same toxic compound, pulegone, as its European counterpart. It should be treated with the same caution, especially regarding its concentrated oil.

Stinging Nettle (Urtica dioica)

This plant resembles a mint with its opposite, jagged leaves but is easily distinguished by the fine, stinging hairs on its stem and leaves. It belongs to a different family and is not a mint. While the sting is not deadly, accidental contact can be unpleasant.

Water Hemlock (Cicuta maculata)

This is one of the most toxic plants in North America and can be mistaken for various edible plants, including some with mint-like appearances. Unlike true mints, water hemlock does not have a square stem, and its leaves do not have a minty scent. This is a critical example of why positive identification is essential before consumption.

Common Edible vs. Poisonous Mints


Characteristic	Safe Mints (e.g., Peppermint, Spearmint)	European Pennyroyal (Mentha pulegium)	Perilla Mint (Perilla frutescens)
Toxicity to Humans	Generally safe in normal culinary amounts.	Highly toxic, especially concentrated oil.	Harmful in large quantities.
Toxicity to Pets	Large amounts can cause digestive upset.	Toxic, contains pulegone.	Highly toxic to livestock.
Growth Habit	Taller, often upright, spreads by rhizomes.	Creeping groundcover, shorter stature.	Erect herb, often in shaded areas.
Leaf Appearance	Toothed, typically larger leaves.	Smaller, rounder leaves.	Green to purplish, oval leaves.
Stem Shape	Square.	Square, but shorter.	Square.
Flowers	Often in spikes at the top of stems.	Delicate purple flowers in whorls.	Flower spikes with bell-shaped flowers.

How to Forage for Mints Safely

Know the Plant: Never rely on scent alone. Use multiple characteristics like stem shape (square stems are a key mint family trait), leaf arrangement (opposite leaves), and flower structure to confirm identity.
Verify Toxicity: Cross-reference your identification with multiple, authoritative sources. When in doubt, leave it out.
Avoid Contamination: Mints can absorb heavy metals or be contaminated by pesticides, so be mindful of where you harvest.
Use Moderation: Even safe culinary mints can cause digestive upset if consumed in excessive quantities.

The Risks for Pets

Many common mints, including peppermint and spearmint, contain essential oils that are mildly toxic to pets in large quantities, causing vomiting and diarrhea. The risk from pennyroyal is much more severe. Catnip (Nepeta cataria), a member of the mint family, is safe for cats in small doses but can also cause digestive issues if over-consumed. For a more comprehensive list of plants toxic to pets, consult the ASPCA Toxic and Non-Toxic Plants List.

Conclusion

While the vast majority of commonly cultivated mints are safe, the presence of dangerous varieties like pennyroyal and perilla mint demands caution. For anyone enjoying mints from their garden or foraging for wild herbs, proper identification is not a suggestion but a necessity. By understanding the key differences between edible and poisonous species, you can safely enjoy the refreshing taste of mint while avoiding potentially harmful mistakes.

Frequently Asked Questions

No, not all mint is edible. While common culinary varieties like spearmint and peppermint are safe, species like European pennyroyal (Mentha pulegium) are poisonous and should never be consumed.

European pennyroyal (Mentha pulegium) is considered the most poisonous mint species. It contains a toxic compound called pulegone, which is especially dangerous in its concentrated essential oil form.

Yes, even safe culinary mints like spearmint can cause an upset stomach, vomiting, or diarrhea if consumed in excessively large quantities.

European pennyroyal grows as a low-creeping groundcover with small leaves and different flower structures than taller, edible mints like peppermint. However, as misidentification is risky, foragers should be absolutely certain before consumption.

Perilla mint is primarily toxic to livestock, but can still be harmful to humans if ingested in large quantities. It is best to avoid consumption entirely.

Some mint look-alikes are also toxic, or in a completely different family and poisonous. For example, water hemlock can be mistaken for mint but is extremely deadly, and American pennyroyal is also toxic.

Catnip is generally safe for cats, but like other mints, excessive ingestion can cause mild digestive upset like vomiting or diarrhea. Pennyroyal, however, is toxic to pets.

No, a minty scent does not guarantee a plant is safe to eat. Some poisonous species and look-alikes can have a similar smell, making other identification traits critical for safety.