Historically, frankincense was used in the Middle East as an ingredient in holy incense for sacrificial ceremonies and to improve communication with the Creator. The French use it for asthma, depression, and ulcers.
This oil acts as an antidepressant, anticancer, antiseptic, and sedative. It is commonly used to treat allergies, bronchitis, colds, headaches, sores, strep throat, and typhoid. Frankincense is generally recognized as safe for consumption by the FDA and can be used topically, diffused, or taken orally.
To learn more about frankincense essential oil and many other pure essential oils, see the book Modern Essentials™: A Contemporary Guide to the Therapeutic Use of Essential Oils.
Sources: Modern Essentials™: A Contemporary Guide to the Therapeutic Use of Essential Oils, 8th Edition, p. 63.