A Traditional Herb with Modern Scrutiny
Shepherd's purse is an annual or biennial plant in the mustard family ($Brassicaceae$), easily identified by its distinctive heart-shaped, triangular seed pods. While many consider it a common weed, it has long been valued in folk medicine for its potent properties. Rich in active compounds like flavonoids, amines, and vitamin K, the herb has a reputation for influencing circulatory health, but modern science has added important caveats and cautions to its use.
Potential Health Benefits
Traditional use and limited modern studies suggest several potential benefits of shepherd's purse, although strong clinical evidence is often lacking for many claims.
- Menstrual Health Support: One of the most well-documented traditional uses is for regulating excessive menstrual bleeding ($menorrhagia$). The European Medicines Agency (EMA) has approved its traditional use for this purpose in adult women, provided serious medical conditions are ruled out. A 2018 study indicated that shepherd's purse extract, alongside a conventional anti-inflammatory drug, reduced menstrual bleeding more effectively than the drug alone.
- Hemostatic Properties: The herb has long been employed as a hemostatic agent to stop bleeding from various sources, including nosebleeds, wounds, and internal bleeding. This is attributed to its vitamin K and tannin content, which aid in blood clotting and constrict blood vessels. A 2017 study found that shepherd's purse extract combined with oxytocin was more effective at reducing postpartum hemorrhage than oxytocin alone. For external wounds, a poultice can be applied.
- Anti-inflammatory and Antioxidant Effects: Research has shown that compounds in shepherd's purse, like polyphenols, possess anti-inflammatory and antioxidant activities. Studies, primarily in cell and animal models, indicate it can reduce the production of inflammatory mediators. These effects may be beneficial for reducing swelling and oxidative stress in the body.
- Diuretic and Kidney Support: In traditional remedies, shepherd's purse is used as a mild diuretic to increase urine production, which helps flush the kidneys and urinary tract. It is sometimes used for conditions like urinary tract infections (UTIs) and kidney stones, though caution is needed due to its oxalate content.
- Digestive and Skin Health: Its astringent properties have been traditionally used to help manage diarrhea and dysentery. Applied topically, it has been used for conditions like eczema, burns, and to help heal minor cuts.
Important Safety Considerations and Risks
Despite its long history, shepherd's purse carries significant risks and is not suitable for everyone. Always consult a healthcare provider before use.
- Contraindications for Pregnancy: Shepherd's purse is considered UNSAFE during pregnancy because it can stimulate uterine contractions, potentially causing miscarriage. Use should be avoided entirely by pregnant individuals.
- Interactions with Medications: The herb can interact with several types of medication:
- Blood Thinners: Because of its blood-clotting properties, it can interfere with anticoagulant drugs, increasing the risk of bleeding.
- Thyroid Medication: It may interfere with thyroid hormone production and treatment, making it inadvisable for those with thyroid conditions.
- Sedatives: When combined with sedative medications, shepherd's purse can exacerbate drowsiness.
- Potential Side Effects: While generally considered safe in small, short-term doses, larger amounts can cause adverse effects, including:
- Drowsiness
- Changes in blood pressure
- Heart palpitations
- Overdose can be serious, potentially causing paralysis, breathing difficulty, and even death, though extremely high doses are required.
- Pre-Surgery Warning: Due to its effects on blood clotting and the central nervous system, shepherd's purse should be discontinued at least two weeks before any scheduled surgery.
Shepherd's Purse vs. Yarrow: A Comparison for Bleeding
When addressing bleeding, shepherd's purse is often compared to another powerful hemostatic herb, yarrow ($Achillea millefolium$). Though both are used to staunch bleeding, their mechanisms and applications differ.
| Feature | Shepherd's Purse ($Capsella bursa-pastoris$) | Yarrow ($Achillea millefolium$) |
|---|---|---|
| Primary Mechanism | Aids blood clotting and promotes uterine contractions | Constricts blood vessels |
| Historical Use | Used widely in European and Asian traditional medicine for both internal and external bleeding | Used by ancient Greeks and Native Americans for wound treatment |
| Effectiveness | Strongest evidence for heavy menstrual and postpartum bleeding | Reputed for stopping bleeding from external cuts and scrapes |
| Cautions | Not for pregnancy, heart/thyroid/kidney issues, or with blood thinners | Avoid during pregnancy and for those with allergies to the Aster family |
Preparing Shepherd's Purse
Shepherd's purse can be prepared in various ways, depending on the intended use. It is important to harvest fresh plants if possible, as some properties are believed to diminish upon drying.
- Infusion (Tea): For internal use, such as for menstrual issues, a tea can be made. Steep 2 teaspoons of the dried herb in a cup of hot water for 15 minutes, and strain before drinking. Dosages and frequency vary, so consulting a practitioner is advised.
- Tincture: A concentrated liquid extract can be made by soaking fresh, minced plant material in alcohol for several weeks. Tinctures allow for more precise dosing, often taken in drops diluted in water.
- Poultice: For topical application to wounds or burns, a poultice can be prepared. This involves crushing the fresh or dried plant material and mixing it with water to form a paste, then applying it directly to the affected area.
- Culinary Use: The young leaves and shoots are edible and can be added raw to salads or cooked in stir-fries, providing a peppery flavor. In some Asian cuisines, it is a popular ingredient in dishes like dumplings.
Conclusion
While traditional use and some preliminary studies suggest that shepherd's purse may offer benefits for managing heavy menstrual bleeding, postpartum hemorrhage, and inflammation, it is a powerful herb with significant risks. Its blood-clotting and uterine-stimulating effects necessitate extreme caution, especially for pregnant women, those with specific medical conditions, or those taking certain medications. The available scientific evidence is limited, and many of its purported benefits are based on traditional use rather than rigorous clinical trials. Therefore, it is crucial to consult a qualified healthcare professional before using shepherd's purse to ensure it is appropriate and safe for your individual health situation.
Authoritative Resource
For an authoritative view on the traditional medicinal use of shepherd's purse in the European Union, refer to the European Medicines Agency (EMA) monograph, which outlines its approved use for heavy menstrual bleeding based on long-standing tradition.
Key Takeaways
- Effective for Bleeding: Clinical studies and traditional medicine support shepherd's purse for reducing heavy menstrual bleeding and postpartum hemorrhage, often in conjunction with conventional treatments.
- Potent Anti-inflammatory: In vitro and animal studies show antioxidant and anti-inflammatory properties, potentially useful for reducing inflammation and cellular damage.
- Strictly Avoid in Pregnancy: Due to its ability to stimulate uterine contractions, shepherd's purse is highly unsafe and contraindicated during pregnancy, as it can cause miscarriage.
- Multiple Contraindications: Individuals with heart conditions, thyroid disorders, or a history of kidney stones should avoid this herb due to potential negative interactions and side effects.
- Not a Substitute for Medical Advice: Despite its traditional uses, the limited clinical evidence for many applications means professional medical consultation is essential before use, especially given its powerful effects.
FAQs
Question: What is shepherd's purse traditionally used for? Answer: It has been traditionally used to stop various types of bleeding (menstrual, postpartum, wounds), as a diuretic, and for issues like digestive discomfort and inflammation.
Question: Is shepherd's purse safe to use during pregnancy? Answer: No, shepherd's purse is considered unsafe during pregnancy. It can stimulate uterine contractions, which may lead to miscarriage.
Question: What are the side effects of shepherd's purse? Answer: Potential side effects include drowsiness, changes in blood pressure, heart palpitations, and alterations in thyroid function, especially in larger doses.
Question: Does shepherd's purse interact with any medications? Answer: Yes, it can interact with blood thinners, sedative medications, and thyroid hormone drugs. Always consult a doctor if you are on medication.
Question: Can shepherd's purse be used for heavy periods? Answer: Based on traditional use and some studies, it is used for heavy periods ($menorrhagia$). The EMA recognizes its traditional use for this purpose in adult women, after serious conditions have been excluded by a doctor.
Question: Is shepherd's purse edible? Answer: Yes, the young leaves and shoots are edible and can be used in salads, soups, and stir-fries. The seeds and seed pods can also be used as a pepper substitute.
Question: What are some alternatives to shepherd's purse for bleeding? Answer: Other herbs like yarrow and lady's mantle are sometimes used for similar hemostatic purposes. They may be used alone or in combination with shepherd's purse in herbal preparations.
