Traditionally, Q. amara is used as a digestive, to treat fever, and against hair parasites (lice, fleas) and mosquito larvae in ponds
In 2011 Husein and Gulam Mohammed, found that Q. amara extract reduced the elevated fasting blood glucose in rats. It also shows that glucose tolerance is increased by the consumption of Q. amara. According to Ferreira and al. 2013, the wood powder of Q. amara shows an anti-hyperglycemic effect, similar to the one from metformin.
Tea made with the leaves of the Q. amara, is used against malaria in the traditional medicine of French Guiana. The tea from Quassia amara has also an effect on the red blood cells counts, the packed cell count, the packed cell volume and hemoglobin concentration. It has an antianemic property.
Quassia amara is used in folk medicine from Costa Rica to reduce the total gastric acidity.
The bitter substances from the Q. amara attack the chitin from the lice larvae and prevent the pupping of new larvae. It also reduce dandruff when used as a hair rinse.
Quassia amara is also used it this traditional Indian medicine, the Ayurvedic medicine to treat rheumatism, alcoholism, dandruff, stomach problems, and worms.