Fever Bark

Reviewed on 6/11/2021
Other Name(s):

Alstonia Bark, Alstonia constricta, Australian Febrifuge, Australian Fever Bush, Australian Quinine, Bitterbark, Corteza de Alstonia, Devil Tree, Devil's Bit, Dita Bark, Écorce Amère d'Australie, Écorce de Quinquina, Écorce de Quinquina d'Australie, Fébrifuge Australien, Pale Mara, Pali-Mara, Quinina Australiana, Quinquina d'Australie.


Fever bark is the bark of the Alstonia tree. People use it to make medicine.

Despite serious safety concerns, fever bark is used for fever, high blood pressure, diarrhea, joint and muscle pain (rheumatism), and malaria. It is also used as a stimulant.

How does it work?

Fever bark contains chemicals that can lower blood pressure.


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Uses & Effectiveness

Insufficient Evidence to Rate Effectiveness for...

  • Fever.
  • High blood pressure.
  • Diarrhea.
  • Malaria.
  • Joint and muscle pain (rheumatism).
  • Use as a stimulant.
  • Other conditions.
More evidence is needed to rate the effectiveness of fever bark for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

Side Effects

Fever bark seems to be UNSAFE. It contains chemicals that can cause side effects such as stuffy nose, irritability, allergic reactions, eye problems, kidney problems, depression, and psychotic reactions. Large doses can cause heart problems and death.


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Special Precautions & Warnings

Pregnancy and breast-feeding: Fever bark seems to be UNSAFE. Avoid using it. It might harm you and your baby.

Depression: Some of the chemicals in fever bark might make depression worse.

Stomach ulcers: Some of the chemicals in fever bark might make stomach ulcers worse.

Schizophrenia: Some of the chemicals in fever bark might cause a psychotic episode.

Surgery: Fever bark acts like a stimulant. There is some concern that it might interfere with surgery by increasing heart rate and blood pressure. Stop using fever bark at least 2 weeks before a scheduled surgery.


Medications used during surgery (Anesthesia)Interaction Rating: Major Do not take this combination.

Fever bark contains a chemical called reserpine. Taking reserpine along with medications used for surgery can cause heart problems. Be sure to tell your doctor what natural products you are taking before having surgery. You should stop taking fever bark at least two weeks before surgery.

Naloxone (Narcan)Interaction Rating: Major Do not take this combination.

Fever bark contains a chemical that can affect the brain. This chemical is called yohimbine. Naloxone also affects the brain. Taking naloxone with yohimbine might increase the chance of side effects such as anxiety, nervousness, trembling, and hot flashes.

PhenothiazinesInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.

Fever bark contains a chemical called yohimbine. Some phenothiazines have effects similar to yohimbine. Taking fever bark and phenothiazines together might increase the effects and side effects of yohimbine.

Some phenothiazines include chlorpromazine (Thorazine), fluphenazine (Prolixin), trifluoperazine (Stelazine), thioridazine (Mellaril), and others.

Stimulant drugsInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.

Stimulant drugs speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and speed up your heartbeat. Fever bark might also speed up the nervous system. Taking fever bark along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with fever bark.

Some stimulant drugs include diethylpropion (Tenuate), epinephrine, phentermine (Ionamin), pseudoephedrine (Sudafed), and many others.


The appropriate dose of fever bark depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for fever bark. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

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Sklar S, et al. Drug therapy screening system. Indianapolis, IN: First Data Bank 99.1-99. 2 eds.

Young DS. Effects of Drugs on Clinical Laboratory Tests 4th ed. Washington: AACC Press, 1995.

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