Another wonderful herb that is used in many places of the world, but is not as common here, is mint. It has traditionally been used to calm digestive troubles and alleviate nausea. Many people enjoy a tea made from peppermint or spearmint leaves, and the volatile oils in both have been used in breath fresheners, toothpastes and chewing gum. Externally, the oil or tea can be used to repel mosquito.