Nose, throat and lung infection are conditions that respond very well to treatment with essential oils. Inhalation is a very effective way of utilizing their properties, for although after arriving in the bronchi the main part will be exhaled directly by the lungs, they cause an increased bronchial secretion (a protective reaction) which is beneficial for many respiratory ailments. By inhalation, they are absorbed into the blood circulation even faster than by oral application. In addition, most essential oils that are absorbed from the stomach are then excreted via the lungs, only a small part in the urine.

Although it is not recommended that essential oils be taken orally, they can by external application effect certain changes in the digestive processes. However, whereas herbal medicine has meny remedies at its disposal for a wide variety of stomach, gall bladder and liver complaints, such as dandelion, marshmallow, chamomile and meadowsweet, much of their effectiveness is based on a combination of aromatic components, together with bitters, tannins and mucilage, which are absent in the volatile oil alone. The external application of essential oils in problems of the digestive system, though effective, is consequently somewhat limited compared with the internal use of herbal remedies.