Skip to main content


Scientific Name(s): Forsythia suspensa (Thunb.) Vahl
Common Name(s): Forsythia, Golden bells, Lian qiao, Weeping forsythia

Medically reviewed by Last updated on Sep 13, 2021.

Clinical Overview


Clinical trials are lacking to support a place in therapy for forsythia. Research interest focuses on chemotherapeutic applications.


There are no recent clinical studies of forsythia to provide a basis for dosage recommendations.


Contraindications have not yet been identified.


Documented adverse effects. Uterine stimulant, emmenagogue. Avoid use.


None well documented.

Adverse Reactions

Forsythia is contraindicated in pregnancy.


Information is limited.

Scientific Family

  • Oleaceae (olives)


F. suspensa is an attractive deciduous shrub native to China. It is often grown ornamentally in the United States for its bright yellow flowers that appear in early spring. There are numerous horticultural varieties that are vegetatively propagated. The Chinese drug is obtained in the fall from the ripe fruits of the cultivated plant. The related species F. viridissima and F. koreana also are used medicinally.


Forsythia fruits are widely used in Chinese traditional medicine for antipyretic and anti-inflammatory activity in the treatment of bacterial infections and upper respiratory ailments. They are commonly combined with honeysuckle flower (Lonicera) and other ingredients. Forsythia fruits are also reputedly used as a diuretic and as a cardiovascular tonic.


Lignans, such as phylligenin and pinoresinol, and their glucosides are major constituents of F. suspensa fruits, while the other species contain related compounds.1 Caffeic acid glycosides with variation in the number of sugars include forsythiaside2 suspensaside3 and a number of forsythosides.4 The reduced cyclohexylethane derivatives rengyol, rengyoxide, and rengyolone5 and their glycosides (rengyosides A-C6 and forsythensides A and B7) have been reported. The distribution of various phenolics among 7 different species of forsythia in leaves and fruits has been studied.8, 9 Rutin is the major flavonoid of all 7 forsythia species.9 Caffeic ester glycosides from related genera of the Oleaceae have been compared.10 Several triterpenes have been isolated from the fruits as well.11 An HPLC assay for major forsythia phenolics has been published.12 The essential oil composition of the fruits has been studied.13

Uses and Pharmacology

Antimicrobial activity

Animal data

Antimicrobial effects, including antiviral activity, have been reported on screening and in vitro studies.3, 4, 14, 25, 26, 27, 28, 29

Clinical data

Research reveals no clinical data regarding the use of forsythia as an antimicrobial agent.


Animal data

Extracts of forsythia have been studied in human tumor cell lines and rodent studies.30, 31, 32

Clinical data

Research reveals no clinical data regarding the use of forsythia in cancer.

Other uses

Antioxidant activity against LDL oxidation has been demonstrated in vitro.20, 33

Anti-inflammatory effects were reported on in older in vitro studies.11, 15, 16, 17, 18

The flavonoid rutin was found to be the active anti-emetic constituent of forsythia fruits using an experimental chicken model of emesis.22


There are no recent clinical studies of forsythia to provide a basis for dosage recommendations.

Pregnancy / Lactation

Documented adverse effects. Uterine stimulant, emmenagogue. Avoid use.23


None well documented.

Adverse Reactions

Use during pregnancy is strictly contraindicated because of its emmenagogue/uterine stimulant properties.


Information is limited. F. suspensa extracts were not mutagenic in Ames tests; however, the incidence of chromosomal aberrations and micronucleated polychromatic erythrocytes in bone marrow of treated mice were somewhat elevated.24

Index Terms

  • Forsythia koreana
  • Forsythia viridissima


1. Nikaido T, Ohmoto T, Kinoshita T, Sankawa U, Nishibe S, Hisada S. Inhibition of cyclic AMP phosphodiesterase by lignans. Chem Pharm Bull. 1981;29(12):3586-3592.6280885
2. Nishibe S, et al. The structure of forsythiaside isolated from Forsythia suspensa. Chem Pharm Bull. 1982;30:1048.
3. Nishibe S, Okabe K, Tsukamoto H, et al. Studies on the Chinese crude drug "Forsythiae Fructus." VI. The structure and antibacterial activity of suspensaside isolated from Forsythia suspensa. Chem Pharm Bull. 1982;30(12):4548-4553.7168874
4. Endo K, et al. Validity of Oriental medicine, part 44. Structures of forsythoside C and D, antibacterial principles of Forsythia suspensa fruits. Heterocycles. 1982;19:2033.
5. Endo K, et al. Structures of rengyol, rengyoxide and rengyolone, new cyclohexylethane derivatives from Forsythia suspensa. Can J Chem. 1984;62:2011.
6. Seya K, et al. Structures of rengyosides A, B and C, three glucosides of Forsythia suspensa fruits. Phytochemistry. 1989;28:1495.
7. Ming D, Yu DQ, Yu SS. New quinoid glycosides from Forsythia suspensa. J Nat Prod. 1998;61(3):377-379.9548879
8. Kitagawa S, et al. Phenolic compounds from forsythia leaves. Phytochemistry. 1984;23:1635.
9. Kitagawa S, et al. Phenolic compounds from forsythia leaves II. Chem Pharm Bull. 1988;36:3667.
10. Andary C, Tahrouch S, Marion C, Wylde R, Heitz A. Caffeic glycoside esters from Jasminum nudiflorum and some related species. Phytochemistry. 1992;31(3):885-886.1368040
11. Ozaki Y, Rui J, Tang YT. Antiinflammatory effect of Forsythia suspensa Vahl. and its active principle. Biol Pharm Bull. 2000;23(3):365-367.10726898
12. Cui Y, Feng SY, Zhao G, Wang MZ. [HPLC analysis of the active ingredients of Forsythia suspensa]. Yao Hsueh Hsueh Pao. 1992;27(8):603-608.1481677
13. Xu Z, et al. Analysis of constituents of essential oil from the Forsythia suspensa (Thunb.) Vahl. Natural Product Res Dev. 1994;6:14.
14. Endo K, et al. Structure of forsythoside A, an antibacterial principle of Forsythia suspensa leaves. Heterocycles. 1981;16:1311.
15. Ozaki Y, Rui J, Tang Y, Satake M. Antiinflammatory effect of Forsythia suspensa Vahl. and its active fraction. Biol Pharm Bull. 1997;20(8):861-864.9300131
16. Kimura Y, Okuda H, Nishibe S, Arichi S. Effects of caffeoylglycosides on arachidonate metabolism in leukocytes. Planta Med. 1987;53(2):148-153.3110811
17. Heilmann J, Calis I, Kirmizibekmez H, Schühly W, Harput S, Sticher O. Radical scavenger activity of phenylethanoid glycosides in FMLP stimulated human polymorphonuclear leukocytes: Structure-activity relationships. Planta Med. 2000;66(8):746-748.11199133
18. Kim N, Kang TH, Song EK, Pae HO, Chung HT, Kim YC. Inhibitory effects of butanol fraction of the aqueous extract of Forsythia koreana on the nitric oxide production by murine macrophage-like RAW 264.7 cells. J Ethnopharmacol. 2000;73(1-2):323-327.11025173
20. Chen C, Chen HY, Shiao MS, Lin YL, Kuo YH, Ou JC. Inhibition of low density lipoprotein oxidation by tetrahydrofurofuran lignans from Forsythia suspensa and Magnolia coco. Planta Med. 1999;65(8):709-711.10630110
22. Yang Y, Kinoshita K, Koyama K, et al. Novel experimental model using free radical-induced emesis for surveying anti-emetic compounds from natural sources. Planta Med 1999;65(6):574-576.10483380
23. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press;1997.
24. Yin X, Liu DX, Wang HC, Zhou Y. A study on the mutagenicity of 102 raw pharmaceuticals used in Chinese traditional medicine. Mutat Res. 1991;260(1):73-82.2027343
25. Li C, Dai Y, Zhang SX, et al. Quinoid glycosides from Forsythia suspensa. Phytochemistry. 2014;104:105-113.24833035
26. Zhang D, Fang J, Chen J, et al. [An in vitro study of anti-human cytomegalovirus effect of Forsythia suspensa and its main active ingredient quercetin] [in Chinese]. Zhongguo Zhong Yao Za Zhi. 2010;35(8):1055-1059.20617693
27. Chen Y, Li X, Zhou JY, Yang QW, Li H. [Effect of an active component from Forsythia suspensa (Thunb.) Vahl against respiratory syncytial virus in vitro] [in Chinese]. Wei Sheng Yan Jiu. 2009;38(6):733-735.20047236
28. Ko HC, Wei BL, Chiou WF. The effect of medicinal plants used in Chinese folk medicine on RANTES secretion by virus-infected human epithelial cells. J Ethnopharmacol. 2006;107(2):205-210.16621378
29. Kong B, Wang J, Xiong YL. Antimicrobial activity of several herb and spice extracts in culture medium and in vacuum-packaged pork. J Food Prot. 2007;70(3):641-647.17388053
30. Ge Y, Wang Y, Chen P, et al. Polyhydroxytriterpenoids and phenolic constituents from Forsythia suspense (Thunb.) Vahl leaves. J Agric Food Chem. 2016;64(1):125-131.26694205
31. Zhao L, Yan X, Shi J, et al. Ethanol extract of Forsythia suspensa root induces apoptosis of esophageal carcinoma cells via the mitochondrial apoptotic pathway. Mol Med Rep. 2015;11(2):871-880.25373392
32. Shin HS, Park SY, Song HG, Hwang E, Lee DG, Yi TH. The androgenic alopecia protective effects of Forsythiaside-A and the molecular regulation in a mouse model. Phytother Res. 2015;29(6):870-876.25808759
33. Chang MJ, Hung TM, Min BS, et al. Lignans from the rruits of Forsythia suspensa (Thunb.) Vahl protect high-density lipoprotein during oxidative stress. Biosci Biotechnol Biochem. 2008;72(10):2750-2755.18838794


This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.

This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.