Quassia, a tree native to Jamaica and its neighboring islands, has traditionally been used as a remedy for roundworms, as an insecticide, and in brewing as a substitute for hops. It has also been used as a bitter digestive aid and a remedy for digestive disorders, parasites, and head lice.
Several early studies performed on quassia verified its traditional use as a natural insecticide, documenting it as an effective treatment for head lice in humans. Since quassia has long been used for malaria in South America, researchers studied this biological effect as well. One study showed strong antimalarial activity in mice.
There is early evidence that quassia may be useful in the treatment of leukemia or gastric ulcers. Quassia may also have pain-relieving, muscle relaxing, and sedating effects, but human clinical trials are currently lacking.

Related Terms

Ailanthus, amargo, bitter ash, bitter bark, bitterholz, bitterwood, bois amer, gorzkla, indaquassin, Jamaican quassia,Jamaica quassia extract, kvassia, kwassi, neoquassin, palo muneco, pau amarelo, pau quassia, pao tariri, picrasma, quassia africana, quassia amarga, quassia bark, quassia indica, Quassia undalata, quassia undulate, quassia wood, quassin, quassinoids, ruda, samaderines, simarinolide, Simaroubaceae (family), Surinam quassia, Surinam wood.

evidence table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Head lice (Grade: C)
Early evidence suggests the effectiveness of quassia for head lice. More well-designed clinical trials are necessary to confirm these finding and make a firm conclusion regarding the safety and effectiveness for this condition.