(also called essential oil) can be toxic and irritating to the skin even in small doses.
You should never ingest it except in coated capsule form. And don’t give peppermint tea or menthol cough drops to children under five years of age; they can cause a choking sensation.
Watch out, too, if you’re prone to heartburn. While menthol’s relaxing of the valve at the entrance to the stomach can soothe cramps by releasing gas, it sometimes also allows stomach acids to splash up into the esophagus, causing that burning sensation in the chest.
What’s the best way to take it?
Enteric-coated peppermint oil capsules are your best bet for indigestion or IBS. They can be expensive, so check with your doctor, naturopath or pharmacist before you try taking them regularly for irritable bowel syndrome.
Peppermint tea doesn’t contain nearly as much menthol (fresh leaves are more potent than packaged teas), but it may ease minor stomach complaints. Pour a cup of boiling water over two teaspoons of crushed leaves and steep for ten minutes. Look for the leaves in specialty produce markets (or grow your own).
You can find peppermint oil and tinctures at most health food stores. Keep in mind, though, that the government doesn’t regulate herbal remedies as strictly as it does drugs, so quality and potency can vary from product to product. There are no required tests for safety or effectiveness, for example. In rare cases, supplements may be contaminated with undesirable substances.