Pennyroyal (Mentha pulegium) is a member of the Lamiaceae family, which includes many commonly known herbs such as basil, mint, and rosemary. This herb has been used for centuries in traditional medicine and culinary practices, with historical references dating back to ancient Greek and Roman times. Pennyroyal was believed to have a range of medicinal properties and was commonly used to treat digestive and respiratory issues. In addition to its medicinal uses, pennyroyal was also used in cooking and as a natural insect repellent. However, while pennyroyal has many potential health benefits, it is important to understand its safe doses and potential toxicity. This article will explore the historical uses, health benefits, phytochemicals, safe doses, and toxicity levels of pennyroyal.