The Medicinal Herb Info site was created to help educate visitors about the often forgotten wisdom of the old ways of treating illnesses. Many of today's drugs and medicines were originally derived from natural ingredients, combinations of plants and other items found in nature.

We are not suggesting that you ignore the help of trained medical professionals, simply that you have additional options available for treating illnesses. Often the most effective treatment involves a responsible blend of both modern and traditional treatments.

We wish you peace and health!


Scientific Names


  • Hedeoma pulegioides L.
  • Mint family

Common Names

  • American pennyroyal
  • Hedeoma
  • Mock pennyroyal
  • Mosquito plant
  • Squaw balm
  • Squawmint
  • Stinking balm
  • Thickweed
  • Tickweed

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Parts Usually Used

The herb and oil
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Description of Plant(s) and Culture

The American species of pennyroyal is an aromatic, soft-hairy annual plant; the erect, square, branching stem grows from 6 to 16 inches high and bears small, opposite, thin, ovate leaves which are sparingly toothed. Axillary clusters of small, tubular, lavender or purplish flowers; calyx two-lipped, with 3 short and 2 longer teeth; appear from June to October. The whole plant has a pleasant, aromatic odor.

European pennyroyal (Mentha pulegium), or true pennyroyal, is similar to the American species in odor and uses. Do not confuse the two herbs.
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Where Found

Found in dry fields and open woods along the Atlantic coast and west to Minnesota and Nebraska.
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Medicinal Properties

Carminative, diaphoretic, emmenogogue (promote menstruation), antispasmodic, mild sedative, sudorific, stimulant, aromatic

Oil: anti-emetic (Do not use in pregnancy), anti-spasmodic, rubrifacent
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Biochemical Information

Ketone puligone and about 1% volatile oil.
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Legends, Myths and Stories

Flavorful and fragrant tea with a somewhat minty taste. Another of the teas used as an oriental tea substitute during the American Revolution.

Back in olden times when abortion was illegal, pennyroyal was used to induce abortion. In some cases it resulted in hemorrhage and serious complications for the mother. Therefore, it should never be used for that purpose. Helps in labor and delivery, though. Do not use without medical supervision.

The oil of this herb is a good insect repellent.

Strip the leaves from the stalk, put the leaves in a muslin bag, sew up the bag and put in pets bed. Fleas are chased away. Or sprinkle with pennyroyal oil or essence.
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Pennyroyal was commonly used in the 19th century medicine to induce perspiration at the beginning of a cold and to promote menstruation. It was taken also with brewer’s yeast to induce abortion. It is helpful against nausea and nervous conditions but should not be taken during pregnancy. Native Americans used pennyroyal tea for headaches and for menstrual cramps, PMS, and pain. The tea also make a good external wash for skin eruptions, bruises, rashes, and itching.

Used for phlegm, respiratory disorders, jaundice, nausea, ulcers, consumption, dropsy, toothache, leprosy, whooping cough, convulsions, sores in the mouth, colic, snakebites, expel after-birth, sore gums, fainting, fever, and gout. Purifies the blood, relieves gas and stomach pain, stimulates uterine contractions. Oil used externally for rheumatism and insect repellent.

Also used as a flavoring.
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Formulas or Dosages

Infusion: use 1 tsp. herb with 1 cup hot water. Take 1 to 2 cups a day.

Tincture: take 20-30 drops at a time, as needed. For children, give small, frequent doses.

Extract: 20-60 drops in liquid daily for relief of symptoms.
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How Sold

The oil externally applied wards off mosquitoes. For this purpose it is used alone or combined with citronella.
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All essential oils are life-threatening if taken internally. To take pennyroyal oil internally to terminate an unwanted pregnancy is very dangerous and in a few cases has resulted in death. There is possible fetal damage from the use of pennyroyal in any form during pregnancy.

Ingesting essential oil can be lethal; contact with essential oil (a popular insect repellent) can cause dermatitis.

May cause severe kidney/liver damage used in excess of 2 ounces.

Do not be used during pregnancy, it is a uterine stimulant.

Use only with medical supervision.
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Buy It! The Herb Book, by John Lust, Bantam Books, 666 Fifth Avenue, New York, NY. copyright 1974.

Buy It! Back to Eden, by Jethro Kloss; Back to Eden Publishing Co., Loma Linda, CA 92354, Original copyright 1939, revised edition 1994

Buy It! Indian Herbalogy of North America, by Alma R. Hutchens, Shambala Publications, Inc., Horticultural Hall, 300 Massachusetts Avenue, Boston, Massachusetts 02115, 1973

Buy It! Earl Mindell’s Herb Bible, by Earl Mindell, R.Ph., Ph.D., Simon & Schuster/Fireside, Rockefeller Center 1230 Avenue of the Americas, New York, New York 10020

Buy It! The Herbalist Almanac, by Clarence Meyer, Meyerbooks, publisher, PO Box 427, Glenwood, Illinois 60425, copyright 1988, fifth printing, 1994

Buy It! Chinese Medicinal Herbs, compiled by Shih-Chen Li, Georgetown Press, San Francisco, California, 1973.

Buy It! Indian Uses of Native Plants, by Edith Van Allen Murphey, Meyerbooks, publisher, PO Box 427, Glenwood, Illinois 60425, copyright 1958, print 1990

Buy It! Eastern/Central Medicinal Plants, by Steven Foster and James A. Duke., Houghton Mifflin Company, 215 Park Avenue South, New York, NY 10000

Buy It! Planetary Herbology, by Michael Tierra, C.A., N.D., O.M.D., Lotus Press, PO Box 325, Twin Lakes. WI 53181., Copyright 1988, published 1992

Buy It! American Folk Medicine, by Clarence Meyer, Meyerbooks, publisher, PO Box 427, Glenwood, Illinois 60425, 1973

Buy It! Prescription for Nutritional Healing, Fifth Edition: A Practical A-to-Z Reference to Drug-Free Remedies Using Vitamins, Minerals, Herbs & Food Supplements, by James F. Balch, M.D. and Phyllis A. Balch, C.N.C., Avery Publishing Group, Inc., Garden City Park, NY

Buy It! Taber’s Cyclopedic Medical Dictionary, 15th Edition, F. A. Davis Company, 1915 Arch Street, Philadelphia, PA 19103

Buy It! Webster’s New World Dictionary, Third College Edition, Victoria Neufeldt, Editor in Chief, New World Dictionaries: A Division of Simon & Schuster, Inc., 15 Columbus Circle, New York, NY 10023

Buy It! An Instant Guide to Medicinal Plants, by Pamela Forey and Ruth Lindsay, Crescent Books (January 27, 1992).

Buy It! The Yoga of Herbs: An Ayurvedic Guide to Herbal Medicine, by Dr. David Frawley & Dr. Vasant Lad, Lotus Press, Twin Lakes, Wisconsin, Second edition, 1988.

Buy It! The Rodale Herb Book: How to Use, Grow, and Buy Nature’s Miracle Plants (An Organic gardening and farming book), edited by William H. Hylton, Rodale Press, Inc. Emmaus, PA, 18049., 1974

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