SCIENTIFIC NAME(S): Hedeoma pulegeoides (L) Persoom and Mentha pulegium L. Family: Labiatae

COMMON NAME(S): American pennyroyal, squawmint, mosquito plant, pudding grass

The herb Pennyroyal ( Mentha pulegium, family Lamiaceae ), is a member of the mint genus; an essential oil extracted from it is used in aromatherapy. Pennyroyal has a traditional folk medicine use in inducing abortions and is an abortifacient . These oils are high in pulegone, a highly toxic volatile, which can stimulate uterine activity.


Pennyroyal has been recorded in history as far back as the 1st century AD, where it was mentioned by Roman naturalist Pliny and Greek physician Dioscorides. In the 17th century, English herbalist Nicholas Culpeper wrote about some uses for the plant, including its role in women's ailments, venomous bites, and digestion. European settlers used the plant for respiratory ailments, mouth sores, and female disorders.The plant's oil has been used as a fleakilling bath, hence the name pulegeoides (from the Latin word meaning flea), and has been used externally as a rubefacient. In addition, the oil found frequent use among natural health advocates as an abortifacient and as a means of inducing delayed menses. The oil and infusions of the leaves have been used in the treatment of weakness and stomach pains.

Botany :- Both plants are members of the mint family and are referred to as pennyroyal. H. pulegeoides (American pennyroyal) grows in woods through most of the northern and eastern US and Canada, while M. pulegium is found in parts of Europe. Pennyroyal is a perennial, creeping herb that possesses small, lilac flowers at the stem ends. It can grow to be 30 to 50 cm in height. The leaves are grayish green and, like other mint family members, are very aromatic.

Uses of Pennyroyal

Pennyroyal may be used as an insect repellent, antiseptic, fragrance, flavoring, as an emmenagogue, carminative, stimulant, antispasmodic and for bowel disorders, skin eruptions, and pneumonia.

Side Effects of Pennyroyal

Pennyroyal can cause abdominal pain, nausea, vomiting, lethargy, increased blood pressure and increased pulse rate, dermatitis and, in large portions, abortion, irreversible renal damage, severe liver damage, and death. A small amount of oil can produce delirium, unconsciousness, shock, seizures, and auditory and visual hallucinations.


For adults (excluding pregnant or nursing women, children, and people with liver or kidney disease), a tea of pennyroyal can be prepared by putting 1-2 teaspoons (5-10 grams) of the herb in 1 cup (250 ml) of boiling water and allowing it to steep for 10-15 minutes. Up to 2 cups (500 ml) per day can be drunk. Pennyroyal tincture can be mixed with a skin cream and applied topically to repel insects, though it is unknown whether this is effective due to a lack of scientific study. The tincture and volatile oil are not recommended for internal use.


Pennyroyal herb teas are generally used without reported side effects (presumably because of low concentration of the oil), but toxicity for pennyroyal oil is well recognized, with many reports of adverse events and fatalities documented.

American or European pennyroyal can cause dermatitis and, in large doses, abortion, irreversible renal damage, severe liver damage, and death. A teaspoonful of the oil can produce delirium, unconsciousness, and shock.

One case of pennyroyal oil ingestion resulted in generalized seizures and auditory and visual hallucinations following the ingestion of less than 1 teaspoonful (5 mL) of the oil; the patient recovered uneventfully. Other symptoms of plant ingestion may include abdominal pain, nausea, vomiting, lethargy, and increased blood pressure and pulse rate.

The major component, pulegone, is oxidized by hepatic cytochrome P450 to the hepatotoxic compound menthofuran. Pulegone, or a metabolite, also is responsible for neurotoxicity and destruction of bronchiolar epithelial cells.

Pulegone extensively depletes glutathione in the liver, and its metabolites are detoxified by the presence of glutathione in the liver. Hepatic toxicity has been prevented by the early administration of acetylcysteine following ingestion of pennyroyal Oil. Various metabolite studies are available regarding hepatotoxicity.

Case reports are widely reported, One woman who ingested up to 30 mL of the oil experienced abdominal cramps, nausea, vomiting, and alternating lethargy and agitation. She later exhibited loss of renal function, hepatotoxicity, and evidence of disseminated intravascular coagulation. She died 7 days after ingesting the oil. Another woman ingested 10 mL of the oil and only experienced dizziness. Two infants (8 weeks of age and 6 months of age) who ingested mint tea containing pennyroyal oil developed hepatic and neurologic injury. One infant died, the other suffered hepatic dysfunction and severe epileptic encephalopathy. A review of 18 previous cases reported moderate to severe toxicity in patients exposed to at least 10 mL of the oil, concluding that pennyroyal continues to be an herbal toxin of concern to public health. Another review concluded that pennyroyal oil is toxic as well.

Pennyroyal is contraindicated in pregnancy. It possesses abortifacient actions (because of pulegone content) and irritates the genitourinary tract. The abortifacient effect of the oil is thought to be caused by irritation of the uterus with subsequent uterine contraction. Its action is unpredictable and dangerous. The dose at which the herb induces abortion is close to lethal, and in some cases it is lethal. However, one letter does report a pregnancy unaffected by pennyroyal use.

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