Forsythia is a shrub. The dried fruit is used for medicine.

Forsythia is used for airway illnesses, swelling, fever, and other conditions. But there is no good scientific research to support any use.
When taken by mouth: There isn't enough reliable information available to know if forsythia is safe or what the side effects might be.

When given by IV: There isn't enough reliable information available to know if forsythia is safe or what the side effects might be.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if forsythia is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.

Surgery: Because forsythia might slow blood clotting, there is a concern that it might cause extra bleeding during and after surgery. Stop taking forsythia at least two weeks before a scheduled surgery.


NatMed Pro rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
Likely effective Effectiveness definitions
Possibly effective Effectiveness definitions
Likely ineffective Effectiveness definitions
Possibly ineffective Effectiveness definitions
Insufficient evidence Effectiveness definitions
  • Fever.
  • Gonorrhea.
  • Heart disease.
  • Nausea and vomiting.
  • Pain and swelling (inflammation).
  • Sore throat (pharyngitis).
  • Swelling (inflammation) of small airways in the lung (bronchiolitis).
  • Swelling (inflammation) of the tonsils (tonsillitis).
  • To increase menstrual flow.
  • Infection of the skin (erysipelas).
  • Other conditions.
More evidence is needed to rate the effectiveness of forsythia for these uses.

Dosing & administration

The appropriate dose of forsythia 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 forsythia. 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.

Interactions with pharmaceuticals

Azithromycin (Zithromax)

Interaction Rating=Minor Be watchful with this combination.

Taking forsythia along with azithromycin might increase the levels of forsythia and azithromycin in the body. This might increase the effects and side effects of both forsythia and azithromycin.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Interaction Rating=Moderate Be cautious with this combination.

Forsythia might slow blood clotting. Taking forsythia along with medications that also slow clotting might increase the chances of bruising and bleeding.

Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.

Interactions with herbs & supplements

Herbs and supplements that might slow blood clotting: Forsythia might slow blood clotting. Taking forsythia along with other natural products that also slow clotting might increase the chances of bruising and bleeding. Some of these products are angelica, clove, danshen, garlic, ginger, ginkgo, Panax ginseng, and others.

Interactions with foods

There are no known interactions with foods.


Forsythia might decrease inflammation. However, more information is needed to determine how forsythia might work.
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This monograph was last reviewed on 01/05/2024 10:00:00 and last updated on 27/12/2021 03:11:50. Monographs are reviewed and/or updated multiple times per month and at least once per year.
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