"Internalizing an essential oil, typically through the mouth.
“Internal use is the process of consuming or otherwise internalizing an essential oil into the body. Only pure, therapeutic-grade essential oils should be used for internal consumption, as other essential oils on the market may be diluted or processed using harmful chemicals." –Modern Essentials®
Some of the most common ways to enjoy internal application is sublingually or with capsules, in beverages and cooking, and by vaginal or rectal insertion.
*"The U.S. Food and Drug Administration (FDA) has approved some essential oils generically for internal use and given them the following designations: GRAS (Generally Recognized As Safe for human consumption), FA (Food Additive), or FL (Flavoring Agent). These designations are listed for each oil that is safe for human consumption in the Single Essential Oils section of [Modern Essentials™] under Oral Use As Dietary Supplement. Oils without this designation should never be used internally without first consulting a certified health care professional” –Modern Essentials®