Definition. - An organic oxide (cineol) obtained from the volatile oil of Eucalyptus globulus and from other sources. It is also found in a great many other volatile oils; oil of cajuput being one of those most widely known.

Description and Properties. - A colorless liquid, having a characteristic, aromatic, and distinctly camphoraceous odor and a pungent, spicy, and cooling taste. Soluble in all proportions in alcohol.

Dose. - 5-10 minims (0.3-0.6 Cc.) [5 minims (0.3 Cc), U. S. P.].

Physiological Action. - Externally and Locally. - Locally applied, the oil of eucalyptus and eucalyptol are more or less irritant, though perhaps less active than many volatile oils. They do not differ in any particular regard from others of this class. The resemblances of eucalyptus to quinine are largely fanciful.

Therapeutics. - Eucalyptus is a valuable remedy in chronic inflammation of mucous membranes, especially in atrophic rhinitis, where it is best applied in spray combined with a liquor petroleum excipient in the proportion of 30-60 minims (2-4 Cc. to the ounce 33 Gm.).

It has proved of service in acute and chronic skin diseases, notably simple dermatitis, and in chronic forms of eczema and psoriasis. As others of the turpentine series, it is a stimulant to sluggish ulcers.

The chief value of this drug lies perhaps in its effects upon the urine in its elimination. It is an active antiseptic and is useful in cystitis and pyelitis.

As a stimulant expectorant eucalyptus is of great value, equaling, if not being superior to, any other remedy in bronchorrhea, pulmonary gangrene, and fetid bronchitis, associated or not with phthisis. Chronic or catarrhal conditions of the lungs and bronchi only are benefited by eucalyptus, acute affections of the bronchopulmonary mucous membrane contraindicating its use. A solution of oil of eucalyptus is used as an antiseptic inhalation in diphtheria.

Administration. - The fresh leaves may be employed as poultices. Any of the preparations may be used, but for internal purposes the oil, or eucalyptol, is preferable, although a good fluid extract is an agreeable form of the medicine. The oil, or eucalyptol, may be given in an emulsion or in capsules, for topical use being diluted with alcohol or oil or incorporated in suppositories or ointments.