FWD 2 Expanded Commission E: Orange peel, bitter

Herbal Medicine: Expanded Commission E

Orange peel, bitter

Latin Name: Citrus aurantium
Pharmacopeial Name: Aurantii pericarpium
Other Names: eville orange, sour orange


Bitter orange is an aromatic variety of citrus that produces highly bitter, acidic fruits. The tree, indigenous to eastern Africa, Arabia, and Syria, was cultivated in India and in Europe by 1200 C.E. Sometimes called Seville orange, bitter orange is produced in Spain, Sicily, Tripoli, California, and Florida (Trease and Evans, 1989). Unripe dried fruits and fruit peels provide ingredients for numerous products. In China, two medicinal preparations are made from bitter orange. In Europe and North America, essential oils distilled from bitter orange flowers (neroli oil) and leaves (petitgrain oil) are commonly used by perfume, cosmetic, and aromatherapy industries (Leung and Foster, 1996). These, and bitter orange oil, flavor many foods, and mask unpleasant tastes in pharmaceuticals.

In traditional Chinese medicine, Zhi qiao, prepared from the dried peel of immature, green fruit, and Zhi shi, prepared from dried fruit, have specific applications, added to formulas that treat mild indigestion, nausea, constipation, and organ prolapse (Huang, 1993).

Like Zhi qiao, Zhi shi is a traditional Chinese treatment for indigestion and anal or uterine prolapse. In its contemporary use in China, it is injected for the treatment of shock syndromes, toxic and anaphylactic shock in particular (Huang, 1993). The herb's positive inotropic effects, observed improvements to circulation of blood through the heart and cerebral tissue, and its amine content, synephrine and N-methyltyramine, validate this use.

The primary indication for bitter orange tincture or extract is heartburn. Dried peel is official in the British Pharmacopoeia as a bitter tonic (Trease and Evans, 1989). Traditional herbalism correlates bitter substances to the digestive tract, and empirical evidence suggests that bitter orange is carminative (Leung and Foster, 1996), mostly likely due to mild spasmolysis. It may also have applications as a topical antifungal agent; oil of bitter orange was effective in curing patients with treatment-resistant fungal skin diseases in recent studies (Ramadan et al., 1996). In vitro tests show that limonene from citrus peels may have relevant anticancer, antitumor, and cell-differentiation promoting activities (Boik, 1995).

Bitter orange extract has been added to herbal weight loss formulas as a replacement for epinephrine. Bitter orange is believed to increase metabolism or thermogenesis due to its synephrine content, and, because of this constituent, it is used in herbal nasal decongestants as an alternative to ephedrine (Sabinsa, 1997). However, the effects of bitter orange in weight reduction, nasal decongestion, and patient safety is still controversial, and awaits clinical assessment. Synephrine, an a1-adrenergic agonist, stimulates a rise in blood pressure through vasoconstriction. N-methyltyramine also raises blood pressure, through norepinephrine depletion (Huang, 1993).


Bitter orange peel is the dried outer peel of ripe fruits of Citrus aurantium L. subspecies aurantium (synonym C. aurantium L. subspecies amara Engler) [Fam. Rutaceae], freed from the white pulp layer, as well as its preparations in effective dosage. The preparation contains essential oil and bitter principles.

Chemistry and Pharmacology

The main constituents include approximately 0.20.5% essential oil; the monoterpenes linalyl acetate, a-pinene, limonene, linalool, nerol, and geraniol; methyl anthranilate; bitter substances; and flavonoids (Wichtl and Bisset, 1994). The flavones present include: tangeretin, tetra-o-methylscutellarin, 3,5,6,7,8,3',4' heptametoxyflavone, nobiletin, sinensetin, auranetin, and 5-hydroxyauranetin (Tang and Eisenbrand, 1992). Active principles in the peel include the alkaloid synephrine and N-methyltyramine (Tang and Eisenbrand, 1992). The carotene pigments found in Citrus species are derived from cryptoxanthin (major), luteoxanthin, mutatochrome, auroxanthin, and zeaxanthin (Tang and Eisenbrand, 1992).

Bitter orange peel contains choleretic, anti-inflammatory, antibacterial, and antifungal activity. Antihypercholesterolemic activity (prevents elevation of serum cholesterol level) in humans and animals is attributed to the constituent pectin (Leung and Foster, 1996).


The Commission E approved the cut peel for loss of appetite and dyspeptic ailments. Bitter orange peel is thought to facilitate weight gain by stimulating the appetite (Bruneton, 1995). The leaf and flower of bitter orange are used, by infusion, for symptoms of neurotonic disorders in both children and adults in cases of minor sleeplessness (Bruneton, 1995; Wichtl and Bisset, 1994). The German Standard License states that the peel is useful 'as a supportive measure in treating stomach complaints, e.g., insufficient formation of gastric juice; to stimulate the appetite' (Wichtl and Bisset, 1994).


None known.

Side Effects

Photosensitization is possible, especially in fair-skinned individuals.

Use During Pregnancy and Lactation

Not recommended.

Interactions with Other Drugs

None known.

Dosage and Administration

Unless otherwise prescribed: 4-6 g per day of cut peel for teas, other bitter-tasting galenical preparations for oral application.

Infusion: 2 g in 150 ml boiled water, three times daily.

Cold macerate: 2 g in 150 ml cold water for 6 to 8 hours stirring occasionally, strain then heat before drinking, three times daily.

Syrupus Aurantii Amarii: 6 g diluted with water or tea infusion.

Fluidextract: 1-2 g (Erg.B.6).

Tincture: 2-3 g (DAB 7).


Boik, J. 1995. Cancer and Natural Medicine: A Textbook of Basic Science and Clinical Research. Princeton, Minnesota: Oregon Medical Press.

Bruneton, J. 1995. Pharmacognosy, Phytochemistry, Medicinal Plants. Paris: Lavoisier Publishing.

Deutsches Arzneibuch, 7th ed. (DAB 7). 1968. Stuttgart: Deutscher Apotheker Verlag.

Ergnzungsbuch zum Deutschen Arzneibuch, 6th ed. (Erg.B.6). 1953. Stuttgart: Deutscher Apotheker Verlag.

Huang, K.C. 1993. The Pharmacology of Chinese Herbs. Boca Raton: CRC Press.

The Japanese Standards for Herbal Medicines (JSHM). 1993. Tokyo: Yakuji Nippo, Ltd. 5253.

Leung, A.Y. and S. Foster. 1996. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics, 2nd ed. New York: John Wiley & Sons, Inc.

Ramadan, W., B. Mourad, S. Ibrahim, F. Sonbol. 1996. Oil of bitter orange: new topical antifungal agent. Int J Dermatol 35(6):448449.

Sabinsa Corporation. 1997. Current Issues: Newsletter of Sabinsa Corporation, October. Available at: www.sabinsa.com/news/nlr1097.htm.

Tang, W. and G. Eisenbrand. 1992. Chinese Drugs of Plant Origin: Chemistry, Pharmacology, and Use in Traditional and Modern Medicine. New York: Springer Verlag.

Trease, G.E. and W.C. Evans. 1989. Trease and Evans' Pharmacognosy, 13th ed. London; Philadelphia: Baillire Tindall.

Wichtl, M. and N.G. Bisset (eds.). 1994. Herbal Drugs and Phytopharmaceuticals. Stuttgart: Medpharm Scientific Publishers.

Additional Resources

BAnz. See Bundesanzeiger.

Bown, D. 1995. Encyclopedia of Herbs and Their Uses. New York: DK Publishing, Inc. 262263.

Braun, R. et al. 1997. Standardzulassungen f r FertigarzneimittelText and Kommentar. Stuttgart: Deutscher Apotheker Verlag.

British Pharmacopoeia (BP). 1980. London: Her Majesty's Stationery Office. Vol. 1:317; Vol 2: 376, 837.

Bundesanzeiger (BAnz). 1998. Monographien der Kommission E (Zulassungs- und Aufbereitungskommission am BGA f r den humanmed. Bereich, phytotherapeutische Therapierichtung und Stoffgruppe). Kln: Bundesgesundheitsamt (BGA).

Deutsches Arzneibuch (DAB 1997). 1997. Stuttgart: Deutscher Apotheker Verlag.

Grieve, M. 1979. A Modern Herbal. New York: Dover Publications, Inc.

Hartke, K. et al. 1991. Deutsches ArzneibuchKommentar. Wissenschaftliche Erlauterungen zum Deutschen Arzneibuch, 10. Ausgabe. [German Pharmacopoeia, 10th ed.Commentary]. Vols. 16. Stuttgart: Wissenschaftliche Verlagsgesellschaft.

Hern ndez, L. et al. Use of medicinal plants by ambulatory patients in Puerto Rico. Am J Hosp Pharm 41(10):20602064.

Meyer-Buchtela, E. 1999. Tee-RezepturenEin Handbuch f r Apotheker und rzte. Stuttgart: Deutscher Apotheker Verlag.

sterreichisches Arzneibuch, Vols. 12, 1st suppl. ( AB). 19811983. Wien: Verlag der sterreichischen Staatsdruckerei.

Pei, D.K. 1985. [Dissolution of retained biliary stones with a compound prescription of orange-peel emulsiona clinical analysis of 134 cases] [In Chinese]. Chung Hsi I Chieh Ho Tsa Chih 5(10):591594, 578.

Pharmacopoeia Helvetica, 7th ed. Vol. 14.(Ph.Helv.VII). 1987. Bern: Office Central Fdral des Imprims et du Matriel.

Reynolds, J.E.F. (ed.). 1989. Martindale: The Extra Pharmacopoeia, 29th ed. London: The Pharmaceutical Press. 1065.

Schilcher, H. 1997. Phytotherapy in Paediatrics: Handbook for Physicians and Pharmacists. Stuttgart: Medpharm Scientific Publishers. 4246.

This material was adapted from The Complete German Commission E MonographsTherapeutic Guide to Herbal Medicines. M. Blumenthal, W.R. Busse, A. Goldberg, J. Gruenwald, T. Hall, C.W. Riggins, R.S. Rister (eds.) S. Klein and R.S. Rister (trans.). 1998. Austin: American Botanical Council; Boston: Integrative Medicine Communications.

1) The Overview section is new information.

2) Description, Chemistry and Pharmacology, Uses, Contraindications, Side Effects, Interactions with Other Drugs, and Dosage sections have been drawn from the original work. Additional information has been added in some or all of these sections, as noted with references.

3) The dosage for equivalent preparations (tea infusion, fluidextract, and tincture) have been provided based on the following example:

  • Unless otherwise prescribed: 2 g per day of [powdered, crushed, cut or whole] [plant part]
  • Infusion: 2 g in 150 ml of water
  • Fluidextract 1:1 (g/ml): 2 ml
  • Tincture 1:5 (g/ml): 10 ml

4) The References and Additional Resources sections are new sections. Additional Resources are not cited in the monograph but are included for research purposes.

This monograph, published by the Commission E in 1994, was modified based on new scientific research. It contains more extensive pharmacological and therapeutic information taken directly from the Commission E.

Excerpt from Herbal Medicine: Expanded Commission E Monographs
Copyright 2000 American Botanical Council
Published by Integrative Medicine Communications
Available from the American Botanical Council.