Pennyroyal tea is made by steeping one to two teaspoons of dried pennyroyal leaves in a cup of hot water for 5 to 10 minutes. It’s a simple herbal infusion with a strong minty flavor, but it comes with serious safety concerns that anyone brewing it needs to understand before taking a sip. The plant contains a compound called pulegone that can cause severe liver damage at high doses, and it has a long, documented history of causing harm when misused.
Brewing Dried Pennyroyal Leaves
The preparation itself is straightforward. Use one to two teaspoons of dried pennyroyal leaves (from either European or American pennyroyal) per cup of water. Bring your water to a boil, pour it over the leaves, and let them steep for 5 to 10 minutes. Strain out the leaves before drinking. A shorter steep produces a milder, lighter tea; a longer steep draws out more of the plant’s volatile oils and creates a stronger, more pungent flavor.
There is a critical distinction between pennyroyal leaf tea and pennyroyal essential oil. The tea made from dried leaves contains relatively small amounts of pulegone, the plant’s toxic compound. The concentrated essential oil, by contrast, contains 85 to 97% pulegone in the European variety and about 30% in the American variety. Pennyroyal essential oil should never be added to tea or taken internally in any form. Nearly every documented case of serious poisoning or death involves the oil, not the leaf infusion.
Why Pennyroyal Is Dangerous
Pulegone, the primary active compound in pennyroyal, is processed by your liver into a toxic byproduct that directly damages liver cells. A review by the European Medicines Agency found that moderate to severe liver damage occurred only in people exposed to at least 10 milliliters of pennyroyal oil, which translates to roughly 5.6 to 8.7 grams of pure pulegone. Fatal liver toxicity has been observed at doses equivalent to 90 to 150 milligrams of pulegone per kilogram of body weight.
Those numbers might sound reassuringly high, but the margin between “a cup of herbal tea” and “a dangerous dose” narrows quickly if someone uses the concentrated oil or drinks large quantities of strong tea. The FDA has not placed formal restrictions on the internal use of pennyroyal, so the oil is still sold and sometimes marketed for menstrual complaints, colds, and other uses. The lack of regulation does not mean it’s safe.
How Pulegone Poisoning Progresses
In documented poisoning cases, symptoms follow a rapid and predictable timeline. Nausea, vomiting, abdominal cramps, and dizziness typically appear within one to two hours of ingestion. Seizures, when they occur, tend to show up within the first three hours. In severe cases, laboratory signs of liver and kidney damage appear within 24 hours. One well-documented fatal case progressed from initial cramping and vomiting to complete multiorgan failure and death in just 46 hours.
These cases overwhelmingly involve pennyroyal oil, not tea brewed from leaves. But the progression illustrates why even moderate overuse is risky: by the time symptoms become serious, the liver damage may already be irreversible.
Safety Limits From European Regulators
The European Medicines Agency has set a tolerable daily intake for pulegone at 0.1 milligrams per kilogram of body weight for food products. For herbal medicinal products used short-term (less than a year), they allow a higher ceiling of up to 75 milligrams per day total. For longer use, the recommended limit drops to 37.5 milligrams per person per day.
The challenge for home brewers is that the pulegone content in a cup of pennyroyal tea varies depending on the plant variety, growing conditions, and how long you steep it. Without lab testing, you have no way to measure exactly how much pulegone is in your cup. This is why most safety guidance around pennyroyal emphasizes keeping consumption occasional and moderate, using only dried leaves (never oil), and keeping steep times short.
Pennyroyal and Pregnancy
Pennyroyal has been used as an abortifacient for centuries. Carl Linnaeus listed it as one in his 1749 medical reference. This is not folklore: animal studies confirm that pennyroyal extracts disrupt placental tissue, lower progesterone levels, raise estrogen levels, and trigger inflammatory responses that can terminate a pregnancy. In rat studies, administration of the extract for just three days during late gestation caused fetal death or severe developmental harm.
Using pennyroyal tea to end a pregnancy is extremely dangerous. The dose needed to affect a pregnancy overlaps with the dose that causes liver failure. Multiple documented deaths involve women who ingested pennyroyal oil attempting to induce abortion. There is no safe, reliable way to use pennyroyal for this purpose at home. If you are pregnant or could be pregnant, avoid pennyroyal entirely.
European vs. American Pennyroyal
Two different plants are both called pennyroyal. European pennyroyal (Mentha pulegium) is a true mint with creeping stems and small purple flowers. American pennyroyal (Hedeoma pulegioides) is a related but distinct species native to eastern North America, with a more upright growth habit and smaller leaves. Both contain pulegone, but in very different concentrations. The essential oil of the European variety is 85 to 97% pulegone, while the American variety’s oil is roughly 30% pulegone.
For tea purposes, either variety can be used, and both carry the same general risks. The European species is more widely available commercially. If you’re foraging rather than buying dried leaves, accurate plant identification matters. Pennyroyal has a distinctly strong, pungent mint smell that helps distinguish it from other wild plants, but confirm your identification with a reliable field guide before consuming anything you’ve gathered yourself.
Practical Precautions
- Use only dried leaves, never essential oil. The oil is far too concentrated for internal use and is responsible for virtually all documented poisoning cases.
- Keep doses small and infrequent. One cup brewed with a single teaspoon of dried leaves, consumed occasionally, stays well within the range that has been used traditionally without reported harm.
- Do not use during pregnancy. The plant actively disrupts pregnancy hormones and placental function.
- Watch for early warning signs. Nausea, cramping, or dizziness after drinking pennyroyal tea are signals to stop immediately. These are the same early symptoms seen in poisoning cases.
- Do not give to children. Lower body weight means a smaller margin of safety, and children’s livers are more vulnerable to toxic insults.