Definition of pennyroyal in English:



  • Either of two small-leaved plants of the mint family, used in herbal medicine.

    • ‘Some herbs that repel fleas include: juniper, pennyroyal, citronella, eucalyptus, cedar and Canadian fleabane.’
    • ‘These include pennyroyal (fatal if ingested), tea tree, rosemary and eucalyptus oils.’
    • ‘Safflower is simply a safe cooking oil, but pennyroyal is known to have potential abortive effects.’
    • ‘Then there's pennyroyal, a name for the mint Menthe pulegium, once prized as a medicinal herb.’
    • ‘For some reason it always showed up in the potted garden and it particularly liked rooming with the pennyroyal.’
    • ‘Herbal flea collars containing essential oils such as pennyroyal, eucalyptus and citronella can also prevent fleas and ticks from landing on your pet.’
    • ‘Essential oils from allspice, basil, cedar, cinnamon, citronella, garlic, geranium, lavender, pennyroyal, peppermint, pine, rosemary, and thyme have been reported to have repellent properties.’
    • ‘Some herbal treatments, such as citrus extracts or pennyroyal, can be toxic to pets and humans.’
    • ‘Mint, lemon balm, pennyroyal, chives, chamomile, mayflower, and summer savory are a few herbs perfectly suited to this microclimate.’
    • ‘This also is true of many herbal tablets, capsules and extracts, including black or blue cohosh, ephedra, dong quai, feverfew, juniper, pennyroyal, St. John's wort, rosemary and thuja.’


Mid 16th century: from Anglo-Norman French puliol (based on Latin pulegium thyme) + real royal.