Quassia is the wood of Quassia excelsa (Simaruba excelsa. De Cand.; Picraena excelsa, Lindley), a lofty tree growing in Jamaica and other West India islands; and of Quassia amara, a small tree or shrub inhabiting Surinam. At present, little or none from the latter source is imported.


Quassia is brought to us in billets, with the bark generally attached; but, as kept in the shops, it is in the form of raspings or shavings, or split into small pieces. The wood is light, porous, yellowish, inodorous, and of an intense, unmixed, and adhesive bitterness.

Active Principle. This is a peculiar, bitter, crystallizable principle, named quassin.

Chemical Relations. Quassia yields its virtues to water and alcohol. Its chemical relations are such as not to interfere with the use of any other medicine, with which it may be desirable to associate it in prescription. It is asserted to have the property of opposing, in some degree, though it will not altogether prevent the putrefaction of animal substances.

Therapeutic Application

The use of quassia as a medicine originated in Surinam, in South America. It was introduced into Europe in the year 1756, but was not made generally known until the publication of a dissertation by Linnaeus in 1763, after which it came quickly into general use. It was at first supposed to have virtues closely analogous to those of Peruvian bark, and was employed in intermittent and remittent fevers, and sometimes also continued fevers, in the low forms of which its antiseptic properties were thought to render it useful. It was considered as especially applicable to cases in which, in consequence of irritability of stomach, the more powerful febrifuge could not be retained. But this use of quassia has been abandoned. It is now generally admitted to be nothing more than a simple bitter, and to be applicable only to affections in which the tonics belonging to this last subdivision are indicated.

Quassia is asserted to be noxious to insect life. Employed in cabinet-ware, it is said to afford protection against insects, and the infusion has been used as a fly-poison. A grain of the alcoholic extract, inserted into a wound in the leg of a rabbit, is said to have caused the death of the animal on the third day, without any signs of inflammation; and from this, and other observations made of its effects on other animals, and on man, it has been supposed to have narcotic properties; but I have never witnessed any effect of this kind, or anything approaching it; and do not believe that it has the least special influence on the brain. In overdoses, its only known effects are to irritate the stomach and bowels.

The uses of quassia are those of the simple bitters generally, of which it is probably the purest and most powerful. For an account of these, the reader is referred to the general remarks on this set of substances. (See page 213.) It is sufficient here to state that the medicine is applicable to all cases of simple weakness of the digestive organs, being much used in dyspepsia, and the debility of convalescence, especially that of febrile diseases and disorders of the alimentary canal, after the entire subsidence of inflammatory action.

In consequence of its noxious influence on worms, it has been employed, in the form of enema, in the treatment of ascarides, and with asserted success. A decoction, made by boiling half an ounce of it in a pint of water, has been used for this purpose.


Quassia has been little used in the form of powder. Some dyspeptic patients, who have no objection to its bitterness, carry the wood along with them in small pieces, and chew it habitually with advantage. But care must be taken that this habit do not grow into an abuse.

The Infusion (Infusum Quassiae, U. S.) is the preparation in which it is most frequently administered. This is made in the proportion of two drachms to a pint of water. Either cold or hot water may be used, the former making a clearer infusion, the latter acting more rapidly.

The officinal Extract (Extractum Quassae, U. S.) is a very efficient preparation, and is preferable when it is desirable to administer the medicine in the form of pill. It is a watery extract, and probably stronger, in a given a weight, than any other preparation of the simple bitters. It is very convenient for combination with other medicines in the pilular form; such as the chalybeates, aloes and rhubarb, myrrh, mercurial pill or calomel, etc.

The Tincture (Tinctura Quassiae, U. S.) is also officinal, and is resorted to, in cases of considerable insensibility of stomach as an addition to the infusion, to other tonic infusions or decoctions, and to liquid purgative preparations.

The dose of the powder is twenty or thirty grains, of the infusion two fluidounces, of the extract from two to five grains, of the tincture one or two fluidrachms; each, three or four times a day.