Peppermint oil is one of the most popular in the world. You recognize the smell and taste immediately. The oil purifies the air and gives a fresh scent to a sick room. Peppermint can be vaporized for all types of colds, flu and coughs. It’s a great expectorant. In hot weather, the oil cools the body. On the skin, mixed with a massage or fatty plant oil, peppermint relieves itching and increases blood flow to the site of application. You can put a drop on your hand and lick it up to aid digestion and fresh breath.