Health Guide


What is it?

Quassia is an herbal medicine used to treat nausea (stomach upset), loss of appetite, and worm infections.

Other names for Quassia include: Bitterwood, Picrasma, Jamaican quassia, Picraena excelsa, and Surinam quassia.

Ask your doctor, nurse, or pharmacist if you need more information about this medicine or if any information in this leaflet concerns you.

Before Using:

Tell your doctor if you

  • are taking medicine or are allergic to any medicine (prescription or over-the-counter (OTC) or dietary supplement)
  • are pregnant or plan to become pregnant while using this medicine
  • are breastfeeding
  • have any other health problems, such as high blood pressure or heart or blood vessel disease


Talk with your caregiver about how much quassia you should take. The amount depends on the strength of the medicine and the reason you are taking quassia. If you are using this medicine without instructions from your caregiver, follow the directions on the medicine bottle. Do not take more medicine or take it more often than the directions tell you to.

To store this medicine:

Keep all medicine locked up and away from children. Store medicine away from heat and direct light. Do not store your medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down and not work the way it should work. Throw away medicine that is out of date or that you do not need. Never share your medicine with others.

Drug and Food Interactions:

Do not take quassia without talking to your doctor first if you are taking:

  • Blood thinning medicine (example: warfarin (Coumadin(R)) (7)


  • Before taking quassia, tell your doctor if you are pregnant or breastfeeding
  • Large amounts may cause vomiting (1)
  • Quassia should be taken 30 minutes before meals (1)

Side Effects:

Stop taking your medicine right away and talk to your doctor if you have any of the following side effects. Your medicine may be causing these symptoms which may mean you are allergic to it.

  • Breathing problems or tightness in your throat or chest
  • Chest pain
  • Skin hives, rash, or itchy or swollen skin

Other Side Effects:

You may have the following side effects, but this medicine may also cause other side effects. Tell your doctor if you have side effects that you think are caused by this medicine.

  • A feeling that your heart is not beating normally (1)
  • Nausea (upset stomach), gagging, and vomiting (throwing up) because quassia is very bitter (1,4)


1. Bradley PR (ed.): British Herbal Compendium, vol. 1. British Herbal Medicine Association, Bournemouth, UK; 1992.

2. Reynolds JEF (ed): Martindale: The Extra Pharmacopoeia, 28th ed. The Pharmaceutical Press, London, UK; 1982.

3. Anon: British Herbal Pharmacopoeia. British Herbal Medicine Association, Keighley, UK; 1983.

4. Duke JA: Handbook of Medicinal Herbs. CRC Press, Boca Raton, FL; 1985.

5. Jensen O et al: Pediculosis capitis treated with quassia tincture. Acta Dermat Venereol Stockholm 1978; 58:557-559.

6. Newall C, Anderson L & Phillipson J. Herbal Medicines: A Guide for Health-Care Professionals. The Pharmaceutical Press, London, UK; 1996.

7. Product Information: COUMADIN(R) oral tablets, IV injection, warfarin sodium oral tablets, IV injection. Bristol-Myers Squibb Company, Princeton, NJ, 2007.

Last Updated: 7/4/2018
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