Definition of quassia in US English:



  • 1A South American shrub or small tree related to ailanthus.

    Genera Quassia and Picrasma, family Simaroubaceae: several species, in particular Q. amara

    • ‘The quassia tree grows from 50 to 100 feet high; it has smooth, gray bark and alternate, odd-pinnate leaves with oblong, pointed leaflets. Its small flowers are yellowish or greenish, its fruit is a small rupe about the size of a pea.’
    • ‘This type of size reduction is of dubious value and is only officially used for quassia which is a hard wood.’
    • ‘Native to tropical America and the Caribbean, quassia grows in forests and near water.’
    1. 1.1 The wood, bark, or root of the quassia, yielding a bitter medicinal tonic, insecticide, and vermifuge.
      • ‘Several early clinical studies performed on quassia verified its traditional use as a natural insecticide, documenting it as an effective treatment for head lice infestation in humans.’
      • ‘A few preparations make use of digestive enzymes, while many others contain plant substances such as chirata, gentian, calama, quassia, orange peel and many spices.’
      • ‘The burning of scents like frankincense and myrrh dates back to the ancient Egyptians, and continued through the centuries, gradually including sweet spices like cinnamon, quassia, cloves, allspice and nutmeg.’
      • ‘There is preliminary evidence that quassia may be useful in the treatment of leukemia or gastric ulcers.’
      • ‘Emetic herbs include bayberry, boneset, buckthorn, culver, false unicorn, lobelia, mandrake, mistletoe, mustard seed, pleurisy, quassia, rue and senega’


Named after Graman Quassi, an 18th-century Surinamese slave who discovered its medicinal properties in 1730.