What is a one-sentence summary of the following article?
Under no circumstances should you apply an essential oil to the skin without diluting it first. Essential oils can cause skin irritation and rashes if used directly on bare skin, so always dilute your oils first.  If you've never used essential oils before, you may want to use diluted oils on a small portion of your skin. Watch for a reaction before massaging them elsewhere on your body. If you have an allergic reaction, you will notice red, flaky skin, pain, and irritation. Cease using the essential oils. The rash should clear up in a few days. Peppermint oil may be effective for treating some symptoms of indigestion. However, for specific health problems, peppermint oil may worsen symptoms.  Peppermint oil can worsen the symptoms of gastroesophageal reflux disease (GERD), and may make gallstones worse. Peppermint oil should not be used on children as it can inhibit breathing. There is not a lot of information on essential oils and pregnancy, so most healthcare providers advise that pregnant women err on the side of caution. It's best to avoid essential oils altogether during pregnancy. However, if you want to use aromatherapy anyway, stick to something like a bath, and only use a couple of drops of essential oils. Ingesting essential oils, or applying them directly to the skin, should be avoided. Parsley seed and pennyroyal oils may be particularly dangerous during pregnancy. You should avoid these oils when you are pregnant.

Summary:
Do not use essential oils directly on the skin. Avoid using peppermint oil in some circumstances. Be careful using essential oils to treat indigestion related to pregnancy.