Peppermint Side Effects and Warnings

Safety Issues

At the normal dosage, enteric-coated peppermint oil is believed to be reasonably safe in healthy adults. ¹ However, case reports and one study in rats hint that peppermint might reduce male fertility . ² The species Mentha spicatamay be more problematic in this regard than the more common Mentha piperita.

Excessive doses of peppermint oil can be toxic, causing kidney failure and even death. Very high intake of peppermint oil can also cause nausea, loss of appetite, heart problems, loss of balance, and other nervous system problems.

Safety in young children, pregnant or nursing women, or those with severe liver or kidney disease has not been established. In particular, peppermint can cause jaundice in newborn babies, so don't try to use it for colic.

Use of peppermint oil may increase levels of the drug cyclosporine in the body. ³ If you are taking cyclosporine and wish to take peppermint oil, notify your physician in advance, so that your blood levels of cyclosporine can be monitored and your dose adjusted if necessary. Conversely, if you are already taking both peppermint oil and cyclosporine, do not stop taking the peppermint without informing your physician. When you stop peppermint, your cyclosporine levels may fall.

Interactions You Should Know About

If you are taking:

• Cyclosporine : Do not use peppermint oil (or stop using it) except in consultation with your physician.