Pennyroyal is an herb in the mint family. The leaves and flowers have been used to treat cold-like symptoms and ease feelings of anxiety. Pennyroyal has also been put on the skin as an oil to keep bugs and insects away. It can be taken by mouth as a pill, powder, or extract. It can also be made into a tea.


There aren’t any advised doses for pennyroyal

What Research Shows

May Be Effective

  • Functional dyspepsia—may improve symptoms and quality of life A1

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely not safe to use pennyroyal on the skin or to take it orally. B1, B2, B4-B6 It may cause liver, kidney, and nervous system problems. B3 Women who are pregnant or breastfeeding and children should not use pennyroyal. B7


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.


REFA Functional Dyspepsia

REFA1 Khonche A, Fallah Huseini H, et al. Efficacy of Mentha pulegium extract in the treatment of functional dyspepsia: A randomized double-blind placebo-controlled clinical trial. J Ethnopharmacol. 2017 Jul 12;206:267-273.

REFB Safety

REFB1 Sullivan JB Jr, Rumack BH, et al. Pennyroyal oil poisoning and hepatotoxicity. JAMA. 1979 Dec 28;242(26):2873-2874.

REFB2 Anderson IB, Mullen WH, et al. Pennyroyal toxicity: measurement of toxic metabolite levels in two cases and review of the literature. Ann Intern Med. 1996 Apr 15;124(8):726-734.

REFB3 De Smet PA. Herbal remedies. N Engl J Med. 2002 Dec 19;347(25):2046-2056.

REFB4 Bunchorntavakul C, Reddy KR. Review article: herbal and dietary supplement hepatotoxicity. Aliment Pharmacol Ther. 2013 Jan;37(1):3-17.

REFB5 Jalili J, Askeroglu U, et al. Herbal products that may contribute to hypertension. Plast Reconstr Surg. 2013 Jan;131(1):168-173.

REFB6 Gordon P, Khojasteh SC. A decades-long investigation of acute metabolism-based hepatotoxicity by herbal constituents: a case study of pennyroyal oil. Drug Metab Rev. 2015 Feb;47(1):12-20.

REFB7 Ahmed M, Hwang JH, et al. Safety classification of herbal medicines used among pregnant women in Asian countries: a systematic review. BMC Complement Altern Med. 2017 Nov 14;17(1):489.

Revision Information

  • Reviewer: EBSCO NAT Review Board Eric Hurwitz, DC
  • Review Date: 07/2019
  • Update Date: 05/08/2020