: a European perennial mint (Mentha pulegium) with small aromatic leaves
: an aromatic North American mint (Hedeoma pulegioides) that has blue or violet flowers borne in axillary tufts and yields an oil used in folk medicine or to drive away mosquitoes

Examples of pennyroyal in a Sentence

Recent Examples on the Web Sadly, pennyroyal is also highly toxic and could have proven deadly to the women taking it. Sara Novak, Discover Magazine, 22 Aug. 2022 Overconsumption of pennyroyal and mugwort, for example, can cause liver failure, according to Ryan Marino, the medical director of toxicology and addiction at the University Hospitals in Cleveland. Rania Soetirto, NBC News, 22 July 2022 Yet pennyroyal contains pulegone, which gets metabolized in the body and forms toxins that can cause liver necrosis, says Josh Trebach, emergency medicine physician and medical toxicologist in Iowa City. Ej Dickson, Rolling Stone, 29 June 2022 Many women turned to herbal remedies such as pennyroyal, which were often effective in terminating pregnancy but could also be toxic. Meredith Blake Staff Writer, Los Angeles Times, 25 Dec. 2020 The findings, published Tuesday in the journal Environmental Entomology, revealed that the most popular plant species among the bees were Oregon checker-mallow and mountain pennyroyal flowers. Kristen Rogers and David G. Allan, CNN, 28 Jan. 2020 Another of Portugal’s cookbook mainstays, Vítor Sobral has opened modestly priced, casual tascas in Lisbon and Brazil that hew closer to traditional flavors yet with lightness and flair, such as Azorean tuna with mango, peppers, and pennyroyal. Anne Farrar, National Geographic, 18 June 2019 Anecdotal evidence shows that cats dislike the smell of lavender, pennyroyal, rue, lemon thyme and Coleus canina (also called scaredy cat plant). Kym Pokorny,, 17 Apr. 2018 Among the essential oils that are toxic to pets are cinnamon, citrus, lemon, pennyroyal, peppermint, pine, sweet birch, tea tree, thyme, wintergreen and ylang ylang. Kim Campbell Thornton, sacbee, 17 Jan. 2018 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'pennyroyal.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


probably alteration of Anglo-French puliol real, from puliol pennyroyal (ultimately from Latin puleium) + real royal

First Known Use

1530, in the meaning defined at sense 1

Time Traveler
The first known use of pennyroyal was in 1530

Dictionary Entries Near pennyroyal

Cite this Entry

“Pennyroyal.” Dictionary, Merriam-Webster, Accessed 4 Dec. 2023.

Medical Definition


pen·​ny·​roy·​al ˌpen-ē-ˈrȯi(-ə)l How to pronounce pennyroyal (audio) ˈpen-i-ˌrīl How to pronounce pennyroyal (audio)
: any of several mints
especially : an aromatic American mint (Hedeoma pulegioides) that yields pennyroyal oil

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