pennyroyal
noun
pen·ny·roy·al ˌpen-ē-ˈrȯi(-ə)l 
ˈpe-ni-ˌrī(-ə)l
ˈpe-ni-ˌrī(-ə)l 1
: a European perennial mint (Mentha pulegium) with small aromatic leaves
2
: 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
Example Sentences
Recent Examples on the Web 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, OregonLive.com, 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
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, OregonLive.com, 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 Word History
Etymology
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
Medical Definition
pennyroyal
noun
pen·ny·roy·al ˌpen-ē-ˈrȯi(-ə)l ˈpen-i-ˌrīl
ˈpen-i-ˌrīl : any of several mints
especially : an aromatic American mint (Hedeoma pulegioides) that yields pennyroyal oil