Peppermint is "a popular flavoring for gum, toothpaste, and tea, is also used to soothe an upset stomach or to aid in digestion," according to the University of Maryland Medical Center. Peppermint can relieve a variety of ailments, including digestive problems, muscle aches and headaches. But peppermint can affect blood pressure values if not used with caution.

The National Center for Alternative and Complementary Medicine defines peppermint a cross between two herbs, water mint and spearmint. Peppermint usually grows throughout Europe and North America. It is often considered a calming herb generally considered safe for adults in very small doses. Peppermint may cause heartburn in some.

Aromatherapy retailers warn patients with high blood pressure to avoid peppermint because it may raise blood pressure. When used in very high amounts, peppermint and its constituent, menthol, may have negative effects on blood pressure. Menthol, often used in over-the-counter cold remedies, also can significantly raise the heart rate.

According to the American Cancer Society, peppermint can have adverse effects that should be considered before it's used: "Peppermint oils, when taken by mouth, can affect the way that other drugs are absorbed by the body and may interfere with antacids, medicines for high blood pressure, and others." If you are taking medication to lower your blood pressure, tell your doctor that you are using peppermint oil to ensure medication effectiveness. The National Institutes of Health warns that you must also check with a doctor before mixing herbal supplements as they may have a combined effect on blood pressure.

Peppermint oil can cause skin irritations and should not be placed directly on the skin. Peppermint can exacerbate gastric reflux conditions and should be avoided by individuals with this condition. The National Institutes of Health states, "Peppermint oil taken by mouth may cause headache, dizziness, heartburn, anal burning, slow heart rate, or muscle tremor." Large doses can cause severe side effects including brain damage. Pregnant and breastfeeding mothers should avoid peppermint because its effects are not fully known.

Peppermint tea is known as a stress reliever. Its calming scent can decrease stress and relieve headaches, and decreasing stress may help to reduce high blood pressure. Peppermint oil is another common use. The oil can be inhaled or mixed into a warm bath, and peppermint capsules are also available. These enteric-coated capsules are used most often for treating irritable bowel syndrome, nausea or gallstones.