- Grindelia camporum
- Asteraceae (family), August flower, California gumplant, grindelia, Grindelia camporum, Grindelia robusta, Grindeliae herba, Grindelie, gum plant, gumplant, gum weed, hardy grindelia, rosin weed, scaly grindelia, tar weed, tarweed.
- Gumweed is a traditional medicine of California Native Americans, such as the Chumash people. Gumweed was used clinically from the 1880s until 1960 in the United States and the United Kingdom for the treatment of asthma, bronchitis, and poison ivy rash. Gumweed use in clinics was discontinued in 1960 when a new law required medicines to have proven efficacy in clinical trials. The plant contains grindelane diterpenoids of unknown pharmacological activity.
- High quality trials supporting the use of gumweed for asthma, bronchitis, dermatitis, or any other condition are currently lacking. High quality clinical trials of gumweed are needed in these areas.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
*Key to grades:
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.
Adults (18 years and older)
- There is no proven safe or effective dose for gumweed. Traditionally, 2 grams of chopped or powdered gumweed, or 2 milliliters of the fluid extract has been used.
Children (younger than 18 years)
- There is no proven safe or effective dose for gumweed in children, and use is not recommended.
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
- Avoid in individuals with a known allergy or hypersensitivity to gumweed.
Side Effects and Warnings
- Based on 80 years of clinical experience and thousands of years of use by California Native Americans, gumweed has a low rate of adverse effects in most healthy people, although this has not been confirmed by clinical trials. Side effects may include slowed heart rate, increased blood pressure, central nervous system depression (in large doses), or lung or kidney irritation.
- Plant preparations should not be used in the eye since they may contain bacteria or fungi. Bacteria and fungi can erode the cornea leading to the need for corneal transplants or the loss of vision. Dropping a solution of gumweed in ethanol onto the eye is not recommended due to the possibility of ethanol (alcohol) irritating the eye.
- Use cautiously in patients with hypertension (high blood pressure) or heart conditions. Avoid using plant preparations on open wounds unless the preparations are known to be sterile.
Pregnancy and Breastfeeding
- Gumweed is not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence. Taking any alcohol and gumweed preparation is not recommended in pregnant women because alcohol may cause the fetal alcohol syndrome (birth defects).
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Interactions with Drugs
- Gumweed may decrease the effects of some drugs that lower blood pressure because it may increase blood pressure. Consult with a qualified healthcare professional, including a pharmacist, as dosing may need monitoring.
- Gumweed may increase the effects of some diuretics, since it may increase urine production.
Interactions with Herbs and Dietary Supplements
- Gumweed may decrease the effects of blood pressure lowering herbs such as Rauwolfia serpentina. Consult with a qualified healthcare professional, including a pharmacist, as dosing may need monitoring.
- Gumweed may increase the effects of diuretic herbs such as juniper.
- Theoretically, gumweed may have additive effects with selenium supplements, since the plant may contain significant amounts of selenium. Too much selenium can interfere with keratin biosynthesis and has other toxic mechanisms as well.
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
- This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration ().
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Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to . Selected references are listed below.